Implement Number.prototype.toPrecision

[NathanRoyer]

This Pull Request closes #349.

It changes the following:

• Implementation of Number.prototype.toPrecision is complete.
• Tests of the aforementioned method were enabled.

[codecov]

Codecov Report

Merging #962 (4146657) into master (4e82a98) will increase coverage by 0.08%.
The diff coverage is 65.71%.

@@            Coverage Diff             @@
##           master     #962      +/-   ##
==========================================
+ Coverage   59.40%   59.48%   +0.08%     
==========================================
  Files         166      166              
  Lines       10717    10780      +63     
==========================================
+ Hits         6366     6413      +47     
- Misses       4351     4367      +16     

Impacted Files	Coverage Δ
boa/src/builtins/number/mod.rs	63.11% <65.71%> (+2.54%)	⬆️

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[Razican]

Test262 conformance changes:

Test result	master count	PR count	difference
Total	78,460	78,460	0
Passed	19,374	19,386	+12
Ignored	15,559	15,559	0
Failed	43,527	43,515	-12
Panics	465	447	-18
Conformance	24.69	24.71	+0.02%

[RageKnify]

The doc comment for to_precision has the wrong link to the spec, it should be https://tc39.es/ecma262/#sec-number.prototype.toprecision , can you fix it please @NathanRoyer?

[NathanRoyer]

@RageKnify Done; the last commit should correct the spec and mdn links :)

[RageKnify]

Hey @NathanRoyer having comments with // 1, // 2, etc matching the spec's steps helps a lot in understanding the code, these are long functions and having each step identified makes it easy to check the "Rust translation", should be easy for you to do and it helps everyone who will one day read the function to understand it.
One thing I think can be changed to more closely follow the spec is in step 3 to use:

boa/boa/src/value/mod.rs

Line 878 in 8f388d5

pub fn to_integer_or_infinity(&self, context: &mut Context) -> Result<IntegerOrInfinity> {

That was recently implemeted and should make the first if a bit clearer.

You can also use the following code to get precision as a Value without needing to use unwrap, you will get Value::undefined if no argument was given.

let precision = args.get(0).cloned().unwrap_or_default();

And for the links you changed the wrong ones 😅 , you changed lines 13-14 but the method's links are in lines 321-322, but don't worry just place the old links back and replaced the method's.

[RageKnify]

It's looking good, just a few more changes to make it easier to read it along with the spec.

[NathanRoyer]

@Razican Hey, I just found 2 bugs earlier today, and I was discussing them on the discord forum... I will include the fixes in my next contribution.