Support for some ES6 features about acorn HOT 13 CLOSED

There is interest in supporting all of ES6, if the ecmaVersion option is set to 6. A patch that starts adding part of such support would be welcome. When parsing ES5, these keywords should remain errors.

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+1 things like yield and let would be great

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const has been available in v8/node.js for a while also. In the interim I'm preprocessing with varify.

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+1 for supporting ES6 import

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Duplicating https://twitter.com/RReverser/status/491714922724986881:

@marijnh Hi, is there a list of ES6 features unsupported in Acorn yet? I'm feeling pretty comfortable with it's code and willing to help.

from acorn.

It seems the only supported feature so far is the spread operator.

If you're doing any work in this direction, make sure you stay compatible with what Esprima is doing (in terms of AST data structure).

from acorn.

Sure. Are you aware of any human-readable list of accepted ES6 features (maybe with specifications) then?

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Asking because MDN Parser API page seems not to match Esprima's output. /cc @ariya

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ES6 feature list

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@mozfreddyb Thanks, but there is mixed draft APIs and syntax from user's perspective, not from parsing+AST specs.

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For those interested, my WIP working fork with ES6 support is available here:

• Repo
• CI test logs

Working features:

• Unicode Code Point Escape Sequences (\u{ABCDEF}).
• Numeric Literals (octal, binary).
• Arrow Functions.
• Spread Element.
• Classes.
• Destructuring assignments.
• Computed object properties.
• Object methods.
• Shorthand object properties.
• for (... of ...) loops.
• Array Comprehensions.
• Modules.
• Template Strings.
• Generators.

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@marijnh Should we close this now or would it better stay open for tracking new upcoming features?

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I think it's fine to close it. We can open new tickets when new features come up.

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