Document detailed naming research

[ljharb]

Document cases where using self, window, or global would break code that is currently using it for environment detection.

[ljharb]

There's a number of examples of window and self both implying a browser, such as https://github.com/Microsoft/automatic-graph-layout/blob/ab371280000f4d85eeedc1899e6faaa66ccad009/GraphLayout/MsaglSharpkit/WebMsagl/Msagl/sharpkit_pre.js . In addition, var self = this is too common a pattern for self to be a safe bet.

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global is a bit less problematic, since browserify automatically transpiles global to window, but here are some example places where global implies node, and node globals like module, process, etc:

• https://github.com/tyskdm/codegs-core/blob/18915f51a1f4de94a4412491b399104d07305aca/code/gas/global.js
• https://github.com/SilentCicero/string.js/blob/f8a052d5cb8375ce6eebfb7eeccb206ab5a8ef90/package-init.js
• https://github.com/noons-hackathon/node-elevator/blob/130ee5a2b244b3a5e0a51d2ba19066b2599c2b3d/floor.js
• https://github.com/sundalei/learnJS/blob/fde94f991f543e44949a0b09c421eaa92ec81521/node/test.js
• https://github.com/jamesmorgan/ethertel/blob/e75603d29c6fdffb91df045ae32f127ccd305875/app/lib/web3/package-init.js

[ljharb]

For posterity, a twitter poll: https://twitter.com/ljharb/status/734450903059570688

[pladaria]

Can this be re-opened?

To me there are no strong reasons to discard self.

There's a number of examples of window and self both implying a browser, such as...

Could you provide a list of those examples? (provided example makes no usage of self). If those examples run in backend, to me that's a minor issue.

var self = this

I've never seen that in modern (ES6+) JS

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Pro self reasons:

• Already exists in browsers, self === window. No breaking changes possible.
• self is the global object in web workers / service workers

From mdn docs:

By using self, you can refer to the global scope in a way that will work not only in a window context (self will resolve to window.self) but also in a worker context (self will then resolve to WorkerGlobalScope.self).

So, looks like making self === global in node (or other non-browser runtimes) is the next logical step.

[kleinfreund]

@pladaria A list of examples is provided in https://github.com/tc39/proposal-global/issues/11#issuecomment-220802575.

I've never seen that in modern (ES6+) JS

I see var self = this; all the time. As for sites that would break, there is a substantial number of live examples that demonstrate this; hence, it is not being considered anymore.

[j-f1]

@kleinfreund Creating a self variable shouldn’t cause an issue since the self will shadow the global self. Again, self already exists on the web, just not on Node.

[obedm503]

I agree with @j-f1. if a variable self is defined as something else, js already treats it as normal. Scoping rules apply as usual.

however, the problem is with node scripts that assume a browser environment if self exists.