Object Rest/Spread Properties

[ariya]

New productions:

PropertyDefinition[Yield] ::
  ...  AssignmentExpression[In, ?Yield]

ObjectAssignmentPattern[Yield] ::
  {AssignmentRestProperty[?Yield]opt}
  {AssignmentPropertyList[?Yield]  ,  AssignmentRestProperty[?Yield]opt}

AssignmentRestProperty[Yield] ::
  ...  DestructuringAssignmentTarget[?Yield]

ObjectBindingPattern[Yield] ::
  {BindingRestProperty[?Yield]opt}
  {BindingPropertyList[?Yield]  ,  BindingRestProperty[?Yield]opt}

BindingRestProperty[Yield] ::
  ...  BindingIdentifier[?Yield]
  ...  BindingPattern[?Yield]

AST changes:

extend interface ObjectPattern {
    properties: [ AssignmentProperty | RestElement ];
}

extend interface ObjectExpression {
    properties: [ Property | SpreadElement ];
}

References:

• The proposal: http://sebmarkbage.github.io/ecmascript-rest-spread/
• Change to the spec: ?
• ESTree for ES2017: https://github.com/estree/estree/blob/master/es2017.md

[hzoo]

ESTree for rest/spread: https://github.com/estree/estree/blob/master/experimental/rest-spread-properties.md

[hzoo]

And it's stage-3 right now (not in es2017)

[ariya]

Originally, the AST changes involved the addition of two new nodes RestProperty and SpreadProperty:

interface RestProperty <: Node {
    type: "RestProperty";
    argument: Expression;
}

interface SpreadProperty <: Node {
    type: "SpreadProperty";
    argument: Expression;
}

and the modifications to ObjectPattern and ObjectExpression:

extend interface ObjectPattern {
    properties: [ AssignmentProperty | RestProperty ];
}

extend interface ObjectExpression {
    properties: [ Property | SpreadProperty ];
}

However, based on the discussion in estree/estree#145, the consensus is that the AST change will be simplified to the reuse of the existing RestElement and SpreadElement and thus the modifications to ObjectPattern and ObjectExpression are also simplified to:

extend interface ObjectPattern {
    properties: [ AssignmentProperty | RestElement ];
}

extend interface ObjectExpression {
    properties: [ Property | SpreadElement ];
}

[ariya]

As of March 2017, it's in Stage 3 (https://github.com/tc39/proposals).

[concubicycle]

Is this currently working?

[ariya]

Is this currently working?

If you use the master branch. Otherwise, keep an eye on https://github.com/jquery/esprima/projects/2.

[idevelop]

Hey @ariya, is version 5.0 scheduled for a release date?

[LeoEatle]

When will 5.0 release?

[danielo515]

Eslint does support this, and eslint uses (by default) esprima. How are they doing this?

[asapach]

ESLint uses Espree: https://github.com/eslint/espree

[danielo515]

Oh, a misread from hours of not sleeping. Thanks!

[ctjlewis]

Three years later, still can't parse a spread operator?

[mreinstein]

There aren't any javascript runtimes that support es module syntax but lack the spread operator. At the very least I would expect esprima.parseModule to support all of the es6-isms.

Also, I'm not sure why this issue has been closed when it's not available in any releases. Isn't this kind of indirectly sweeping the problem under the rug?

[VityaSchel]

How do I replace it? I tried replacing ... with {}.apply() — Unexpected identifier {, with new Object().apply() — Unexpected identifier, with fake object which does not exist in code: object.apply() — Unexpected identifier .. None of these work. Is there any workaround?

[ctjlewis]

This issue should not be closed.

[LeoEatle]

I publish a master version of esprima: https://www.npmjs.com/package/esprima-master
But I still suggest to use Babel or Eslint as parser. I have finished this in my project.

[0x00C5]

There's a solution here #2034 (comment)

[sophiawisdom]

Six years and no support for spread operator.

[VityaSchel]

Six years and no support for spread operator.

use babel