walk.js aborts with error if input contains ES6 code

[sergejmueller]

Perhaps because walk.js does not support ES6?

Example: start.js.txt

TypeError: types[type] is not a function
    at walk (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/walk.js:17:16)
    at Object.skip (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/types.js:293:3)
    at walk (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/walk.js:17:16)
    at Object.exports.BinaryExpression.exports.LogicalExpression.exports.AssignmentExpression (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/types.js:243:3)
    at walk (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/walk.js:17:16)
    at Object.skip (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/types.js:293:3)
    at walk (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/walk.js:17:16)
    at Object.exports.ExpressionStatement (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/types.js:32:3)
    at walk (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/walk.js:17:16)
    at Object.skip (/usr/local/lib/node_modules/optimize-js/node_modules/walk-ast/lib/types.js:293:3)

[nolanlawson]

I'm using acorn and acorn-walk. Maybe there's a way to make it support ES6?

[sergejmueller]

I don't know. A another acorn-walk plugin? https://npmdaily.com/search/acorn

[austinkelleher]

This may not work for your use case, but I transpile to ES5 using Babel and then use optimize-js.

[nolanlawson]

@Rich-Harris would switching to https://www.npmjs.com/package/estree-walker solve this?

[Rich-Harris]

@nolanlawson yes

[sanex3339]

esprima has nice support of es6 and es7
https://github.com/jquery/esprima
https://github.com/estools/estraverse
https://github.com/estools/escodegen

[lattsi]

this is already patched with the use of estree-walker.

[benderTheCrime]

Question: wouldn't it just be possible to give acorn different options? For instance, imports/exports should work just fine if the sourceType: 'module' option was provided.