babel-plugin-transform-es2015-function-name should not create function names with reserved words. (T7235)

[babel-bot]

Issue originally made by @Hypercubed

Bug information

• Babel version: 6.6.5
• Node version: 4.2.3
• npm version: 3.5.2

Options

babel-plugin-transform-es2015-function-name via babel-preset-es2015 via babel-preset-es2015-rollup

Input code

Input:

export const test = {
  await: a => 2 * a
}

Output:

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
var test = exports.test = {
  await: function await(a) {
    return 2 * a;
  }
};

Description

await is a reserved word (when found in module code). It is valid in the input as an object property but invalid in the output as the function name.

[babel-bot]

Comment originally made by @Hypercubed

Some discussion here: rollup/rollup#564

[babel-bot]

Comment originally made by @Hypercubed

Is it possible to confirm this is a bug or not? Currently, I'm using the following to avoid generating an invalid function name:

export const test = {
  [`await`]: a => 2 * a
}

This also works:

export const test = {
  await: function _(a) { return 2 * a; }
}

[babel-bot]

Comment originally made by @loganfsmyth

We could probably debate either way on for the code output, but it'd probably be better to err on the side of compatibility, so we should update out reserved word logic to avoid this.

On the other side, Babylon appears to parse await as an identifier, even with sourceType: 'module' which is definitely a bug, but would probably count as a breaking change so we'd have to wait for a major version bump to do that.

[danez]

I filled estools/esutils#24 to fix this.

[sateffen]

bump - Still not merged, even though the merge-requests looks good. This is an anoying bug when using babel with d3.

[hzoo]

We should just land #4954 or do it ourselves then?

[hzoo]

#4952 landed in master, need to release