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lib: refactor primordials.uncurryThis #36221

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lib: refactor primordials.uncurryThis #36221

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16 changes: 5 additions & 11 deletions lib/internal/per_context/primordials.js
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Expand Up @@ -12,17 +12,11 @@
// `primordials.Object` where `primordials` is a lexical variable passed
// by the native module compiler.

const ReflectApply = Reflect.apply;

// This function is borrowed from the function with the same name on V8 Extras'
// `utils` object. V8 implements Reflect.apply very efficiently in conjunction
// with the spread syntax, such that no additional special case is needed for
// function calls w/o arguments.
// Refs: https://github.com/v8/v8/blob/d6ead37d265d7215cf9c5f768f279e21bd170212/src/js/prologue.js#L152-L156
function uncurryThis(func) {
return (thisArg, ...args) => ReflectApply(func, thisArg, args);
}

// `uncurryThis` is equivalent to `func => Function.prototype.call.bind(func)`.
// It is using `call.bind(bind, call)` to avoid using `Function.prototype.bind`
// after it may have been mutated by users.
const { bind, call } = Function.prototype;
const uncurryThis = call.bind(bind, call);
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not that this isn't a very cool application, but wouldn't this be a bit clearer?

const uncurryThis = (f) => Function.prototype.call.bind(f)

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@aduh95 aduh95 Nov 22, 2020 •
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The issue is that Function.prototype.bind can be modified by the user. I could add a comment explaining it though. Do you think that would be enough?

Suggested change
const uncurryThis = call.bind(bind, call);
// The following line is equivalent to `const uncurryThis = f => call.bind(f);`.
const uncurryThis = call.bind(bind, call);

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Ah yeah I guess once you factor it out you just end up with call.bind(bind, call). A comment would be good then.

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Done, PTAL.

primordials.uncurryThis = uncurryThis;

function copyProps(src, dest) {
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