fix(compiler): Allow BigInt usage in templates

[shadowings-zy]

What kind of change does this PR introduce? (check at least one)

• Bugfix
• [ x ] Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• [ x ] No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• [ x ] It's submitted to the dev branch for v2.x (or to a previous version branch), not the master branch
• [ x ] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• [ x ] All tests are passing: https://github.com/vuejs/vue/blob/dev/.github/CONTRIBUTING.md#development-setup
• [ x ] New/updated tests are included

If adding a new feature, the PR's description includes:

• [ x ] A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:
Hello!
This pull request is related to issue #11126 . Now we can use BigInt in "Mustache" syntax.
I had already added test for this feature in "test/unit/features/filter/filter.spec.js".
And all tests are passing.

Close #11126

[posva]

Hi, thanks for the PR but this is not what was mentioned on the issue. The idea is to allow the use of BigInt when it's available and fail if it's not. See https://jsfiddle.net/syrnaefq/. This should work on browsers supporting BigInt. It's similar to allowing Number in templates. The syntax 100n seems to already work when it's supported by the browser.
The goal is not to polyfill the feature

[shadowings-zy]

That makes me a little confused...
In my pull request," {{ BigInt(100) }}" and "{{ 100n }}" both work when BigInt is available, and fail if it is not ( and my PR will warn 'BigInt is not support! ' )

It seems that the idea of this issue is the same to my PR🤦‍♂️？
@posva

see this test:

  it('bigint support', () => {
    const vm = new Vue({
      template: `<div>{{ BigInt(BigInt(10000000)) + BigInt(2000000000n) * 3000000n }}</div>`
    }).$mount()
    expect(vm.$el.textContent).toBe('6000000010000000')

[shadowings-zy]

Did you mean: 'We need to "{{ BigInt(100) }}" and "{{ 100n }}" both work when BigInt is available, and fail if it is not' like ' "{{ Number(100) }}" and "{{ 100n }}" both work'?

If so, I get your point and I will fix it in this way.

[shadowings-zy]

Hi @posva !
I revert the previous commits and I rewrite the code to allow BigInt usage in templates.
As you see it just like allow Number in template.

If it's OK, please merge this PR, if not, let's discuss further : )

[posva]

I think it's fine to not use a conditional, the same way we allow Intl even though it's not supported before IE 11

[shadowings-zy]

OK，That sounds right，and I will add BigInt directly in makeMap()
: )

[posva]

let's put it up after the Intl, the comment is not really necessary

[shadowings-zy]

OK~, I fixed it in commit#4241f12

[posva]

Thanks

[posva]

@shadowings-zy can you undo the merge you did? it seems to have messed up the PR

[shadowings-zy]

@shadowings-zy can you undo the merge you did? it seems to have messed up the PR

@posva Sorry, I forgot I use dev branch to open this PR, and now I undo my merge.