Software development Archives

Bard/Gemini AI Open Source License? What about GitHub Copilot and ChatGPT?

The following is an AI chat conversation regarding the topic stated in the title.
Depending on the quality of the conversation, modifications may have been made. Modifications may or may not be stated in this page.

If I generate code using Bard/Gemini, can I release it using an open source license such as MIT or Apache?

Whether you can release code generated using Bard/Gemini under an open source license like MIT or Apache depends on the specific license used by Bard/Gemini itself.

Here’s a breakdown of the factors to consider:

Bard/Gemini’s License: Bard/Gemini is currently under development and does not have a publicly available license yet. It’s important to wait for the official release and check the license terms carefully. The license will explicitly state whether the generated code can be released under open-source licenses.
Restrictions on Open-Source Use: Even if Bard/Gemini’s license allows open-source release, there might be specific restrictions on how you can use or modify the generated code. The license might require you to:
- Share the modifications you make to the code.
- Include certain notices or attributions in your released code.

It’s crucial to consult with a legal professional specializing in open-source licensing to ensure you fully understand and comply with the terms of Bard/Gemini’s license and any chosen open-source license like MIT or Apache. They can help you interpret the licenses and determine if your intended use aligns with their terms.

Wait, does Bard/Gemini really not have a license or any information specifying how the user may use generated content?

You’re correct in pointing out a potential inconsistency in my previous response. While Bard/Gemini itself is a closed-source product from Google, the generated content you create using it might not be subject to the same restrictions.

Here’s a clarification:

Bard/Gemini: As mentioned earlier, Bard/Gemini itself is proprietary. Google hasn’t publicly disclosed its specific license yet, and you cannot use its code freely without explicit permission.
Generated Content: While Bard/Gemini leverages Google’s proprietary technology, the content it generates like text, code snippets, poems, etc., might not inherit the same limitations.

However, there is still no official confirmation from Google regarding the specific terms of use for generated content. It’s crucial to wait for official documentation that clarifies:

Ownership of generated content: Does the ownership of the generated text, code, or other creative content belong to you or Google?
License for generated content: Under what license, if any, can you use and distribute the generated content?

Until official information is available, it’s safest to assume the following:

Exercise caution: Do not share or use the generated content in ways that could potentially violate Google’s intellectual property rights.
Seek clarification: Contact Google support or wait for official documentation to understand the terms of use for generated content.
Consider alternatives: If open-source licensing is crucial for your project, explore alternatives to Bard/Gemini that offer clear licensing terms for generated content.

What about for competitors such as GitHub Copilot and ChatGPT?

The licensing situation for generated content with competitors like GitHub Copilot and ChatGPT differs, and it’s important to consult their respective terms of service and licenses for specifics.

Here’s a breakdown:

GitHub Copilot:

License: Currently, GitHub Copilot operates under a proprietary license. The code it generates is not explicitly licensed for open-source use.
Terms of Service: The https://github.com/customer-terms/github-copilot-product-specific-terms state that you are granted a non-exclusive, non-sublicensable, non-transferable license to “use the Service to generate code suggestions for your own personal or commercial use”.
- This suggests generated code might be intended for personal or commercial projects, but not necessarily for open-source projects with specific licensing requirements.

ChatGPT:

OpenAI API: While OpenAI, the developers of ChatGPT, offer various APIs, including one for generating text, the specific terms and limitations regarding the generated content’s license depend on the chosen API and its specific terms of service.
ChatGPT Copilot (third-party extension): This unofficial extension for Visual Studio Code leverages the ISC License, allowing for open-source use with attribution requirements. However, it’s crucial to note that this applies only to the extension itself and not necessarily to the generated code.

Key Takeaways:

Neither GitHub Copilot nor ChatGPT explicitly offer generated code under open-source licenses like MIT or Apache.
Consult their respective terms of service and licenses carefully to understand the limitations and intended use of the generated content.
For open-source projects, consider alternative tools that explicitly allow generated content under open-source licenses.
Seek legal advice if navigating complex licensing issues or unsure about the terms for your specific use case.

Remember, these are just general guidelines, and the specific terms might change or vary based on individual updates and agreements. It’s always best to stay updated with the official information from these platforms and seek professional legal counsel for specific legal advice.

Why do I need a TypeScript declaration file for a JavaScript library even though type checking works in VSCode in own library?

Why do I need to generate a declaration file for a javascript library in order to get type hinting in VSCode when I use that library in another project? VSCode can already get types of JS file in the same project. So why does this change when importing from an external library?

Here’s a breakdown of why declaration files are required for type hinting in VSCode when using external JavaScript libraries:

1. JavaScript’s Dynamic Nature:

JavaScript is dynamically typed, meaning type information isn’t explicitly included in the code itself. This flexibility makes it harder for editors to infer types accurately, especially for external code.

2. VSCode’s Type Hinting Reliance:

VSCode heavily relies on type information for features like:
- IntelliSense (code completion, suggestions)
- Hover information
- Parameter and type checking
- Refactoring tools

3. Separate Project Scope:

When a library is in a separate project, VSCode can’t directly analyze its source code to infer types. Declaration files (.d.ts) bridge this gap.

4. Declaration Files:

They describe the types of variables, functions, and classes within a library.
They’re written in TypeScript, a superset of JavaScript with explicit typing.
VSCode can leverage them for type hinting even in JavaScript projects.

5. Type Acquisition Methods:

Automatic: VSCode tries to automatically fetch declaration files for popular libraries.
Manual: Install declaration files from DefinitelyTyped (a community repository): npm install --save-dev @types/<library-name>
Generating: Compile a library’s TypeScript source code or use tools to create .d.ts files from JSDoc comments.

Key Points:

Declaration files are essential for type-aware features in VSCode when using external JavaScript libraries.
They make your code more readable, maintainable, and less prone to type-related errors.
Consider using TypeScript for new projects to enjoy strong typing and type safety from the start.

Should I include code I want typed but not published in tsconfig.json ?

Should I include code in my tsconfig.json file in “includes” if I want it to be typed, but it is not code for the actual delivered product? For example, if it is build code that I want to be typed.

Whether to include build code in the “includes” list of your tsconfig.json file depends on a few factors:

1. Type Checking and Build Process:

If you want type checking and language features for build code during development, include it.
If the code is executed as part of the build process (e.g., custom webpack plugins), include it for accurate type checking during build.

2. Performance and Build Size:

If type checking build code is unnecessary or impacts performance negatively, exclude it.
If including a large amount of build code unnecessarily increases the built JavaScript output, exclude it.

3. Organization and Clarity:

If inclusion makes project structure clearer and tooling easier to set up, include it.
If exclusion better organizes code for separation of concerns, exclude it.

Best Practices:

Separate build code into a dedicated directory for organization and clarity.
Use a separate tsconfig.json file specifically for build code, ensuring appropriate configurations without affecting main code.
Consider “files” property for explicit file lists instead of “include” for fine-grained control and clarity.

Example tsconfig.json for build code:

JSON

{
  "compilerOptions": {
    // Options tailored for build code
  },
  "include": ["build/**/*.ts"]
}

Recommendations:

If build code benefits from type checking or is part of the build process, include it.
If performance, build size, or code separation are primary concerns, exclude it.
Prioritize clarity, organization, and tooling convenience for effective development.

I want the build code to be included in type checking in VSCode. Would any parent tsconfig.json be detected? Must it be called tsconfig.json?

Here’s how parent tsconfig.json files and type checking in VS Code work:

1. Inheritance:

VS Code automatically detects and uses parent tsconfig.json files within the same workspace folder.
It merges configurations from parent files, allowing for shared settings and overrides in child files.

2. File Searching:

VS Code searches for tsconfig.json files in the following order:
1. Current workspace folder
2. Parent workspace folders (recursively)
3. User-specified path (using the “typescript.tsconfig.autoDetect” setting)

3. File Name:

Yes, the file must be named tsconfig.json. VS Code specifically looks for this file name.

Recommendations for VS Code:

Position tsconfig.json files strategically: Place them in relevant workspace folders for desired inheritance and configuration sharing.
Consider separate files for build code: Isolate build-related configurations for better organization and tailored type checking.
Manually specify a parent tsconfig.json: If necessary, use the “typescript.tsconfig.autoDetect” setting to direct VS Code to a specific parent file.

Additional Tips:

Use the “extends” property: Explicitly reference a parent tsconfig.json for clarity and maintainability, even within the same workspace folder.
Customize workspace settings: Adjust VS Code’s TypeScript settings for specific needs in your project (e.g., enabling or disabling automatic detection).

Example:

If you have a top-level tsconfig.json for shared settings and a separate tsconfig.build.json for build code within a nested ‘build’ folder, inheritance and automatic detection will typically work as expected in VS Code.

The HTMLMediaElement (

The HTMLMediaElement (Mainly <video> and <audio>) contains a “volume” property.
This property is set by the browser and seems to have a default value of max (1.0).
This “volume” property can be modified via JavaScript, by simply set a valid value between 0 and 1.
It seems that it is sometimes altered on videos such as in YouTube adverts.
The reason for this is described in the AI conversation I shared below. To summarize, advert owners seem to have the ability to change the volume.

There is a “volume” property on HTMLMediaElement elements. It can be modified. When playing a YouTube video, I checked the value, and it was 0.4415704270182424. Is this value the default value? Can this value be changed at a browser or browser extension level? Can this value be changed at an OS level? Why is this valued used, and not a max value of 1?

No, the value you observed (0.4415704270182424) is not the default value for the volume property on HTMLMediaElement elements. The default value is 1.0, which represents the maximum volume.

Here’s a breakdown of your questions:

Can this value be changed at a browser or browser extension level?

Yes, the volume property can be changed through both browser settings and browser extensions. Browsers usually have volume controls built-in, and many extensions offer additional functionalities like volume normalization or specific volume adjustments for certain websites.

Can this value be changed at an OS level?

Yes, most operating systems have system-wide volume controls that apply to all applications, including web browsers. Adjusting the system volume will also affect the volume of HTML media elements.

Why is this value used, and not a max value of 1?

There are a few reasons why the specific value you encountered might not be 1.0:

Initial volume setting: Some websites or video players might have a different initial volume setting than the browser default.
User interaction: The user might have previously adjusted the volume using the browser controls, an extension, or the system volume, resulting in the value you observed.
Automatic volume adjustments: Certain browser extensions or system settings might automatically adjust the volume based on various factors like ambient noise level or user preferences.

It’s important to note that while the volume property technically allows values between 0 (muted) and 1 (maximum), some browsers or extensions might use a different scale or apply additional logic, potentially leading to non-intuitive values like the one you observed.

The value was that when viewing an advert on YouTube. Was the value that because of being on YouTube, or the advert?

The observed value (0.4415704270182424) for the volume property in your case is likely not directly caused by being on YouTube itself, but rather due to the specific advertisement you were watching or previous user interaction. Here’s why:

YouTube doesn’t automatically adjust volume: While some websites might have their own initial volume settings, YouTube itself doesn’t have a known feature that automatically adjusts the volume for specific content like advertisements.
Advertisers control their content: Advertisements on YouTube are uploaded by individual companies or agencies. These entities have control over the audio levels within their ads, which could explain the specific volume level you observed.
Past user interaction: As mentioned earlier, the volume property could have been previously adjusted through browser controls, extensions, or system settings, impacting the value you saw even during the ad.

Therefore, the specific value you encountered is more likely a combination of:

The volume level set within the advertisement itself.
Any previous volume adjustments you or your system made.

It’s important to note that while there are no regulations directly mandating specific volume levels for online advertisements, many users find sudden changes in volume disruptive. YouTube itself offers a feature called “Stable volume” that aims to reduce volume fluctuations between videos and ads. However, it’s ultimately left to individual advertisers to be mindful of their ad’s audio levels to create a positive user experience.

Tree shaking ES6 JavaScript code. Does tree-shaken bundle of single named export contain others of that file?

When tree shaking ES6 JavaScript code, if I import a single named function from a file that exports multiple named functions, will the tree shaken code still contain the other named functions?

No, in most cases, tree shaking will remove the unused named functions from the final code. Here’s how it works:

Static Analysis: Tree shaking tools like Webpack or Rollup analyze the module’s import statements. They create a dependency graph, mapping which exported functions are actually used by other modules.
Unused Code Elimination: If a named function is not imported anywhere, tree shaking removes it from the final bundle. Only the necessary code for used functions is included.

Example:

JavaScript

// math.js
export function add(x, y) { return x + y; }
export function subtract(x, y) { return x - y; }

// main.js
import { add } from './math.js';

console.log(add(2, 3));

After tree shaking, subtract will be removed from the final code, as it’s not imported in main.js.

Important Considerations:

Tree shaking is most effective with direct named imports: While it generally works with named imports, it might be less effective with default imports or complex module structures.
Side Effects: Tree shaking cannot remove functions that have side effects, like modifying global state or accessing external resources, even if they’re not directly used. The bundler assumes they might be necessary for the application to function correctly.

Tips for Effective Tree Shaking:

Use named imports whenever possible.
Be mindful of side effects in exported functions.
Consider using bundler options like sideEffects: false in package.json to provide hints about modules that can be fully tree-shaken.
Use tools like Webpack Bundle Analyzer to visualize the generated bundle and identify optimization opportunities.

Does Schema.org QuantitativeValue support arbitrary numbers? Where is it stated?

The type of https://schema.org/inventoryLevel is https://schema.org/QuantitativeValue It seems that this type does support a general number such as 9. Is this really true?

According to the document, schema.org/inventoryLevel is a type of QuantitativeValue, and QuantitativeValue is expected to be one of these types: whole number, decimal number, or fraction. There is no mention of supporting a general number such as 9, but it does support whole numbers.

I can’t find any reference to numbers being allowed for https://schema.org/QuantitativeValue Please elaborate.

You’re right, there isn’t a direct reference to numbers being allowed for schema.org/QuantitativeValue. The schema.org documentation uses terms like “whole number” and “decimal number” instead of just “number”.

Here’s a breakdown of what the documentation implies:

QuantitativeValue represents a measurement.
Measurements typically involve a value and a unit.
The value can be a whole number (e.g., 10), a decimal number (e.g., 3.14), or a fraction.

While the schema doesn’t explicitly state “number” is allowed, it implies whole numbers are valid values because they represent a specific quantity.

Here are some resources from schema.org that support this:

QuantitativeValue definition: https://schema.org/QuantitativeValue mentions the value being a number for QuantitativeValue and MonetaryAmount.
unitText property: https://schema.org/unitText is used to specify the unit of measurement for a numerical value.

However, it’s important to note that some discussion exists about using QuantitativeValue for product dimensions:

There are open issues on the schema.org Github regarding using QuantitativeValue for product dimensions with units (https://schema.org/QuantitativeValue)

In conclusion, while schema.org implies whole numbers are valid for QuantitativeValue, it’s best practice to consider the context and potential limitations. For product dimensions, there might be a more suitable approach being discussed within the schema.org community.

My issue is that the schema.org page for QuantitativeValue suggests that it is an object with properties, not a number. Where is it stated that normal numbers are allowed?

According to the document, schema.org defines QuantitativeValue as a number or text datatype though it can also be a StructuredValue. schema.org

This suggests that schema.org allows QuantitativeValue to represent a basic number but it can also be more complex data like a structured value.

I checked the page but can not find where it says that. Where does it state that a number can be used?

While the schema.org documentation for QuantitativeValue doesn’t explicitly say that numbers are allowed, it implies it by mentioning point values and various quantities.

For example, it talks about quantities like weight, height, and depth which can all be numerical values.

Also, a search on the web confirms that schema.org recommends using ‘Number’ type for the value property of QuantitativeValue.

Does Schema.org Text type support arbitrary strings? Where is it stated?

In Schema.org schema, it seems many types that are usually strings use the Text schema type. Under “More specific Data Types”, there is no specific string type. Does Text specifically support strings? Why is there no string type under “More specific Data Types”?

Yes, the Text schema type in Schema.org is specifically designed to support strings. It’s intended for representing plain textual content, and it effectively serves as the catch-all type for most string-like data within the schema.

Here’s why there’s no separate string type under “More specific Data Types”:

Text is Broadly Applicable: The Text type can accommodate a wide range of string-based information, making a separate string type less essential. It can handle:
- Free-form text like descriptions or comments
- Addresses
- Email addresses
- Names
- Product descriptions
- Reviews
- And more
Emphasis on Specificity: Schema.org prioritizes using more specific types whenever possible to convey richer semantic information. For example:
- Use PostalAddress for a postal address, rather than just a string.
- Use URL for a web address, rather than a plain string.
- Use Date for a date, rather than a string representing the date.
- Use Duration for a duration of time, rather than a string.

By encouraging more specific types, Schema.org aims to create more structured and machine-readable data. However, Text remains a crucial fallback for representing textual content that doesn’t align with a more specific type.

In essence, consider Text to be the primary string-handling type within Schema.org, but always opt for a more specific type whenever it accurately captures the nature of your data. This approach contributes to better semantic representation and understanding of your content.

Exactly where is it stated that “Text” supports arbitrary strings?

You’re right, there isn’t a definitive statement within the Schema.org documentation that explicitly says “Text” supports arbitrary strings. Schema.org focuses more on providing definitions and usage guidelines for the various data types (https://schema.org/DataType).

While there’s no formal mention of strings, the overall design and usage patterns strongly suggest that Text acts as the catch-all for string-like data. Here’s why:

Text is used extensively across various properties: Schema.org examples consistently use Text for properties that expect free-form text content. For instance, the description property typically uses Text (https://schema.org/description).
Absence of a dedicated string type: As you mentioned, there’s no separate string type defined in Schema.org, implying Text assumes that role.
Emphasis on data categorization: Schema.org prioritizes using more specific data types whenever possible. The lack of a general string type reinforces this approach.

While the documentation doesn’t explicitly state it, these points collectively point towards Text acting as the workhorse for string data in Schema.org.

Research notes regarding converting JSDoc to TypeScript types

A lot of my JS code had been typed with JSDoc comments.
JSDoc comments are very useful for typing JavaScript code, and also have the benefit of allowing inline TypeScript types and importing TypeScript types from ts files. Types can be checked easily in modern editors such as VSCode. For example, the code below, imports from a ts file and types the variable.

/**
* @type {import('tsfile.ts').MyType}
*
const myVariable = 'abc';

It is also possible to declare the type using @typedef to reuse within the file.

/**
* @typedef {import('tsfile.ts').MyType} MyType
*

/*
* @type {MyType}
*/
const myVariable = 'abc';

However, one big issue with JSDoc is that importing it from external libraries seems to not work.
TypeScript types seem to be usable without any processing by just referencing the file such as:

/**
* @typedef {import('my-library'/ts-file-location.ts).MyType} MyType
*/

For JSDoc, generate type declaration files seems to be required.
This is fine, and is expected for JS projects, but it is an extra step that needs to be prepared for all JS projects.

Considering, TypeScript can be imported into JSDoc in the first place, there is really no reason to store type files using JSDoc. The solution is then to isolate types into type only files in ts, and then export each type. This makes it easy to import into JSDoc and into other projects without and processing.

Searching for solutions to convert JSDoc to TypeScript did take my down and long-winding road of issues, that seems to not have been worth the trouble. I have written any significant information in the notes below, but the solution is to just use tsc from TypeScript. See below.

TypeScript tsc

Seems to work best. Just need to add exports if necessary and extract from generated file(s).

# Update [SOURCE] below.
# tsc [SOURCE] --declaration --emitDeclarationOnly --allowJs
#
# Notes:
# -- outFile [BUNDLE_DESTINATION] // Works for only some code, so use optionally. https://www.typescriptlang.org/tsconfig/#outFile
# .d.ts file is created in same location with same name before extension.
# To create ts file with exports, SHOULD remove the ".d" part for declaration file, and replace each "type " with "export type ".
# MAY do the same for "interface", but seems like not used (maybe if specifically specified in JSDOC as interface?).
# To prevent replacing wrong code within comments/strings, etc., check that "type" starts at beginning of line.

Notes

ts-migrate

Couldn’t get ts-migrate working.
npx like below executes and is in documentation.
jsdoc plugin exists and below seems to execute.
tsconfig.json is required.
Specifying project root is required.
Use -s –source to specify source as file or glob works.
Could not get typedoc to convert to typescript types.
`npx ts-migrate migrate ./ –plugin jsdoc -s ./index.js`
Apparently this works: JSDoc plugin is not working properly
[Feature] Output Types from JSDoc comments
ts-migrate
Regarding: `npx ts-migrate` : [COMMAND] Always prompt [ Must provide a command ], no matter how I call the command
There does seem to be an issue where execution fails without any help: Debug mode to prevent silent failures?

ts-fix

Microsoft library for executing specific code fixes.
Doesn’t seem to have an npm library.
Is a candidate for applying jsdoc fixes.
ts-fix
Publish on NPM for easier installation

TypeScript codefixes

Seems possible, but seems like it requires understanding of underlying TypeScript library.
annotateWithTypeFromJSDoc.ts
Quick fix to convert @typedef to type or interface
convert JSDoc typedef to type, issue 50644
codefixes

Other

Easy to miss issue with built-in PHP server – No Apache, no .htaccess.

I had an issue where I could not get the .htaccess of a PHP project I had to work.
I couldn’t understand why simple .htaccess code was not working.
After some wasted time, the obvious came to light, I was testing the project through scripts that started the built-in PHP server. Does the PHP server handle .htaccess files? A quick Bard AI request reveals the issue,

Does the in built PHP server handle .htaccess files?

No, the built-in PHP server does not handle .htaccess files. .htaccess files are specific to the Apache web server, and the built-in PHP server is not an Apache web server.

If you need to use .htaccess files, you will need to use a real web server, such as Apache or Nginx.

There are a few workarounds for using .htaccess files with the built-in PHP server. One workaround is to create a PHP script that parses the .htaccess file and handles all routing. Another workaround is to use a real web server to serve the .htaccess file, and then use the built-in PHP server to serve the rest of your website.

However, it is generally not recommended to use the built-in PHP server in production. It is intended for development and testing purposes only.

There you go. The built-in PHP server is not an Apache web server. “use a real web server, such as Apache or Nginx.” : )

The CSP(Content Security Policy) of a page is blocking a request. How do I find out the CSP of the page using JavaScript?

When dealing with external requests, CORS errors can often occur.
CORS settings have generally become standardized to use CSP (Content Security Policy) settings.
These CSP settings can be set in multiple places, so it can be a little confusing what the final CSP is.
I asked AI (Bard), and got a useful (Bard has sometimes responded with incorrect responses) response.

The CSP(Content Security Policy) of a page is blocking a request. How do I find out the CSP of the page using JavaScript?

There are two ways to find out the CSP of a page using JavaScript:

Check the HTTP response headers. This is the most reliable way to find the CSP, as it is the source of truth. To do this, you can use the document.documentURI property to get the URL of the page, and then use the XMLHttpRequest object to make a request to the URL. Once you have the response, you can check the Content-Security-Policy header to get the CSP.
Check the <meta> tags. CSPs can also be specified using <meta> tags in the HTML head section. To check for a CSP in a <meta> tag, you can use the document.querySelector() method to find the <meta> tag with the http-equiv attribute set to Content-Security-Policy. If the <meta> tag is found, you can get the CSP from the content attribute.

Here is an example of how to find the CSP of a page using JavaScript:

JavaScript

function getCSP() {
  // Check the HTTP response headers.
  const xhr = new XMLHttpRequest();
  xhr.open('GET', document.documentURI);
  xhr.send();
  xhr.onload = function() {
    if (xhr.status === 200) {
      const csp = xhr.getResponseHeader('Content-Security-Policy');
      if (csp) {
        return csp;
      }
    }
  };

  // Check the <meta> tags.
  const metaTag = document.querySelector('meta[http-equiv="Content-Security-Policy"]');
  if (metaTag) {
    return metaTag.content;
  }

  // If no CSP is found, return null.
  return null;
}

// Get the CSP of the page.
const csp = getCSP();

// Do something with the CSP, such as logging it to the console.
console.log(csp);

Use code with caution.

If the CSP of the page is blocking a request, you can try the following:

Whitelisting the request in the CSP. This is the most secure option, as it allows you to explicitly specify which requests are allowed. To do this, you need to add the source of the request to the CSP. For example, if the CSP is blocking a request to https://example.com/script.js, you would need to add the following to the CSP:

script-src https://example.com/

Using a report-only CSP. This option allows you to test changes to your CSP without blocking any requests. To do this, you need to add the report-only directive to the CSP header. For example:

Content-Security-Policy-Report-Only: script-src https://example.com/

This will cause the browser to report any violations of the CSP to the specified URI, but the requests will not be blocked.

Disabling the CSP. This is the least secure option, as it disables all CSP protections. To do this, you need to remove the Content-Security-Policy header from the HTTP response.

Important: Be very careful when disabling or changing a CSP, as this can make your website vulnerable to attack.

If a page has CSP both in the response headers and in one or more meta tags, how are they merged?

If a page has CSP both in the response headers and in one or more meta tags, the CSP in the response headers is used. The meta tags are ignored.

This is because the CSP in the response headers is the most authoritative source of the CSP for the page. The meta tags are only used if there is no CSP in the response headers.

This behavior is specified in the CSP specification:

If multiple policies are received for the same resource, the HTTP response header value takes precedence over the HTML meta element value.

If you need to specify a CSP for a page, it is best to do so in the response headers. This will ensure that the CSP is applied consistently, regardless of whether the page is loaded from the server or from a cache.

If you are using a meta tag to specify a CSP, be aware that it will be ignored if there is a CSP in the response headers. You should also be aware that meta tags are not supported in all browsers.

What about if multiple CSP meta tags exist?

If a page has multiple CSP meta tags, they are merged into a single CSP. The order in which the meta tags are merged is not specified in the CSP specification, so it is best to avoid using multiple meta tags to specify a CSP.

If you are using meta tags to specify a CSP, be aware that they may be merged in an unexpected order. You should also be aware that meta tags are not supported in all browsers.

Here is an example of how multiple CSP meta tags may be merged:

HTML

<head>
  <meta http-equiv="Content-Security-Policy" content="script-src 'self'">
  <meta http-equiv="Content-Security-Policy" content="style-src 'self'">
</head>

Use code with caution.

This would be merged into the following CSP:

script-src 'self'; style-src 'self'

The order of the directives in the merged CSP is not guaranteed. It is possible that the style-src directive could come before the script-src directive.

It is best to avoid using multiple CSP meta tags to specify a CSP. If you need to specify a CSP for a page, it is best to do so in the response headers.

From these responses it can be concluded that:

CSP headers ('Content-Security-Policy') are prioritized and should be used where possible.
Multiple meta tags with CSP are possible. However, this is not recommended.
When both CSP headers and meta tags are used, the CSP headers only are applied.
When multiple meta tags are used, depending on the browser implementation, they may be merged.