I'm interesting in how JS source code works and seems that I should to use ECMAScript® Language Specification. In my case I tried to write my own implemetetion of Function.prototype.call
Function.prototype._call = function (thisArg = {}, ...arg) {
// 1. Let func be the this value.
let func = this
// 2. If IsCallable(func) is false, throw a TypeError exception.
if (typeof func !== 'function') {
throw new TypeError(this + "isn't callable")
}
// 3. Perform PrepareForTailCall().
thisArg.func = func
// 4. Return ? Call(func, thisArg, args).
return thisArg.func(...arg)
}
It works, but I'm not sure that my implementation is correct and would like to compare it with the "official" implementation. Where may I find code references for ECMAScript examples? Thank you!
Is there an official implementation of ECMAScript Language Specification?
Such an implementation is known as a reference implementation, rather than an "official" implementation, as surely every conforming and certified (is that even a thing for ECMAScript?) implementation is "official".
But yes, there is - but as far as I can tell, only ECMAScript 4 from 2007 has (had?) an actual reference implementation which was available to download from the ECMAScript.org website.
https://lambda-the-ultimate.org/node/2289
ECMAScript Edition 4 Reference Implementation
The first pre-release of the reference implementation of ECMAScript Edition 4 (a.k.a. JavaScript 2) is now available. We've created a new web site for information about the ECMAScript specification and reference implementation. You can download source and binary forms of the reference implementation.
No, there is no reference implementation for ECMAScript, the definitive authoriative source is the specification itself - see also its Conformance section. It is accompanied by the official Test262: ECMAScript Test Suite
The closest to what you are looking for would be the Engine 262 project.