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Merge pull request #7491 from loganfsmyth/require-array-rest-spread-i…
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…terable

Explicitly throw if the array rest/spread items are not iterable.
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@loganfsmyth
loganfsmyth committed Mar 8, 2018
2 parents 828e9a8 + eaa31b6 commit 1c9b0ff
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Showing 3 changed files with 123 additions and 72 deletions.
177 changes: 109 additions & 68 deletions packages/babel-helpers/src/helpers.js
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Original file line number Diff line number Diff line change
Expand Up @@ -616,70 +616,6 @@ helpers.set = () => template.program.ast`
}
`;

helpers.slicedToArray = () => template.program.ast`
// Broken out into a separate function to avoid deoptimizations due to the try/catch for the
// array iterator case.
function _sliceIterator(arr, i) {
// this is an expanded form of \`for...of\` that properly supports abrupt completions of
// iterators etc. variable names have been minimised to reduce the size of this massive
// helper. sometimes spec compliancy is annoying :(
//
// _n = _iteratorNormalCompletion
// _d = _didIteratorError
// _e = _iteratorError
// _i = _iterator
// _s = _step
var _arr = [];
var _n = true;
var _d = false;
var _e = undefined;
try {
for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) {
_arr.push(_s.value);
if (i && _arr.length === i) break;
}
} catch (err) {
_d = true;
_e = err;
} finally {
try {
if (!_n && _i["return"] != null) _i["return"]();
} finally {
if (_d) throw _e;
}
}
return _arr;
}
export default function _slicedToArray(arr, i) {
if (Array.isArray(arr)) {
return arr;
} else if (Symbol.iterator in Object(arr)) {
return _sliceIterator(arr, i);
} else {
throw new TypeError("Invalid attempt to destructure non-iterable instance");
}
}
`;

helpers.slicedToArrayLoose = () => template.program.ast`
export default function _slicedToArrayLoose(arr, i) {
if (Array.isArray(arr)) {
return arr;
} else if (Symbol.iterator in Object(arr)) {
var _arr = [];
for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
_arr.push(_step.value);
if (i && _arr.length === i) break;
}
return _arr;
} else {
throw new TypeError("Invalid attempt to destructure non-iterable instance");
}
}
`;

helpers.taggedTemplateLiteral = () => template.program.ast`
export default function _taggedTemplateLiteral(strings, raw) {
if (!raw) { raw = strings.slice(0); }
Expand Down Expand Up @@ -725,23 +661,128 @@ helpers.temporalUndefined = () => template.program.ast`
export default {};
`;

helpers.slicedToArray = () => template.program.ast`
import arrayWithHoles from "arrayWithHoles";
import iterableToArrayLimit from "iterableToArrayLimit";
import nonIterableRest from "nonIterableRest";
export default function _slicedToArray(arr, i) {
return arrayWithHoles(arr) || iterableToArrayLimit(arr, i) || nonIterableRest();
}
`;

helpers.slicedToArrayLoose = () => template.program.ast`
import arrayWithHoles from "arrayWithHoles";
import iterableToArrayLimitLoose from "iterableToArrayLimitLoose";
import nonIterableRest from "nonIterableRest";
export default function _slicedToArrayLoose(arr, i) {
return arrayWithHoles(arr) || iterableToArrayLimitLoose(arr, i) || nonIterableRest();
}
`;

helpers.toArray = () => template.program.ast`
export default function _toArray(arr) {
return Array.isArray(arr) ? arr : Array.from(arr);
import arrayWithHoles from "arrayWithHoles";
import iterableToArray from "iterableToArray";
import nonIterableRest from "nonIterableRest";
export default function _toConsumableArray(arr) {
return arrayWithHoles(arr) || iterableToArray(arr) || nonIterableRest();
}
`;

helpers.toConsumableArray = () => template.program.ast`
import arrayWithoutHoles from "arrayWithoutHoles";
import iterableToArray from "iterableToArray";
import nonIterableSpread from "nonIterableSpread";
export default function _toConsumableArray(arr) {
return arrayWithoutHoles(arr) || iterableToArray(arr) || nonIterableSpread();
}
`;

helpers.arrayWithoutHoles = () => template.program.ast`
export default function _arrayWithoutHoles(arr) {
if (Array.isArray(arr)) {
for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) arr2[i] = arr[i];
return arr2;
} else {
return Array.from(arr);
}
}
`;

helpers.arrayWithHoles = () => template.program.ast`
export default function _arrayWithoutHoles(arr) {
if (Array.isArray(arr)) return arr;
}
`;

helpers.iterableToArray = () => template.program.ast`
export default function _iterableToArray(iter) {
if (
Symbol.iterator in Object(iter) ||
Object.prototype.toString.call(iter) === "[object Arguments]"
) return Array.from(iter);
}
`;

helpers.iterableToArrayLimit = () => template.program.ast`
export default function _iterableToArrayLimit(arr, i) {
// this is an expanded form of \`for...of\` that properly supports abrupt completions of
// iterators etc. variable names have been minimised to reduce the size of this massive
// helper. sometimes spec compliancy is annoying :(
//
// _n = _iteratorNormalCompletion
// _d = _didIteratorError
// _e = _iteratorError
// _i = _iterator
// _s = _step
var _arr = [];
var _n = true;
var _d = false;
var _e = undefined;
try {
for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) {
_arr.push(_s.value);
if (i && _arr.length === i) break;
}
} catch (err) {
_d = true;
_e = err;
} finally {
try {
if (!_n && _i["return"] != null) _i["return"]();
} finally {
if (_d) throw _e;
}
}
return _arr;
}
`;

helpers.iterableToArrayLimitLoose = () => template.program.ast`
export default function _iterableToArrayLimitLoose(arr, i) {
var _arr = [];
for (var _iterator = arr[Symbol.iterator](), _step; !(_step = _iterator.next()).done;) {
_arr.push(_step.value);
if (i && _arr.length === i) break;
}
return _arr;
}
`;

helpers.nonIterableSpread = () => template.program.ast`
export default function _nonIterableSpread() {
throw new TypeError("Invalid attempt to spread non-iterable instance");
}
`;

helpers.nonIterableRest = () => template.program.ast`
export default function _nonIterableRest() {
throw new TypeError("Invalid attempt to destructure non-iterable instance");
}
`;

helpers.skipFirstGeneratorNext = () => template.program.ast`
export default function _skipFirstGeneratorNext(fn) {
return function () {
Expand Down
8 changes: 6 additions & 2 deletions packages/babel-plugin-transform-modules-commonjs/test/fixtures/regression/T7199/output.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,9 +4,13 @@ var _foo = _interopRequireDefault(require("foo"));

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { "default": obj }; }

function _sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }
function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest(); }

function _slicedToArray(arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return _sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }
function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance"); }

function _iterableToArrayLimit(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }

function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

const _bar = bar,
_bar2 = _slicedToArray(_bar, 1),
Expand Down
10 changes: 8 additions & 2 deletions packages/babel-traverse/src/scope/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -401,7 +401,7 @@ export default class Scope {
console.log(sep);
}

toArray(node: Object, i?: number) {
toArray(node: Object, i?: number | boolean) {
const file = this.hub.file;

if (t.isIdentifier(node)) {
Expand Down Expand Up @@ -431,14 +431,20 @@ export default class Scope {
);
}

let helperName = "toArray";
let helperName;
const args = [node];
if (i === true) {
// Used in array-spread to create an array.
helperName = "toConsumableArray";
} else if (i) {
args.push(t.numericLiteral(i));

// Used in array-rest to create an array from a subset of an iterable.
helperName = "slicedToArray";
// TODO if (this.hub.file.isLoose("es6.forOf")) helperName += "-loose";
} else {
// Used in array-rest to create an array
helperName = "toArray";
}
return t.callExpression(file.addHelper(helperName), args);
}
Expand Down

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