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Unify spec and loose code
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@nicolo-ribaudo
nicolo-ribaudo committed Mar 14, 2020
1 parent 07a6f7b commit 40ce663
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Showing 3 changed files with 73 additions and 160 deletions.
14 changes: 7 additions & 7 deletions packages/babel-helpers/src/helpers.js
View file
Expand Up @@ -1043,15 +1043,15 @@ helpers.createForOfIteratorHelperLoose = helper("7.9.0")`
export default function _createForOfIteratorHelperLoose(o) {
var i = 0;
if (Array.isArray(o)) {
return function() {
if (i >= o.length) return { done: true };
return { done: false, value: o[i++] };
}
}
if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) {
if (Array.isArray(o))
return function() {
if (i >= o.length) return { done: true };
return { done: false, value: o[i++] };
}
if (typeof Symbol === "undefined" || o[Symbol.iterator] == null)
throw new TypeError("Invalid attempt to iterate non-iterable instance.\\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
}
i = o[Symbol.iterator]();
return i.next.bind(i);
Expand Down
213 changes: 64 additions & 149 deletions packages/babel-plugin-transform-for-of/src/index.js
View file
Expand Up @@ -79,37 +79,45 @@ export default declare((api, options) => {
};
}

const pushComputedProps = loose
? pushComputedPropsLoose
: pushComputedPropsSpec;

const buildForOfArray = template(`
for (var KEY = 0, NAME = ARR; KEY < NAME.length; KEY++) BODY;
`);

const buildForOfLoose = template.statements(`
for (var ITERATOR_HELPER = CREATE_ITERATOR_HELPER(OBJECT), STEP_KEY;
!(STEP_KEY = ITERATOR_HELPER()).done;) {}
!(STEP_KEY = ITERATOR_HELPER()).done;) BODY;
`);

const buildForOf = template.statements(`
var ITERATOR_HELPER = CREATE_ITERATOR_HELPER(OBJECT), STEP_KEY;
try {
for (ITERATOR_HELPER.s(); !(STEP_KEY = ITERATOR_HELPER.n()).done;) {}
for (ITERATOR_HELPER.s(); !(STEP_KEY = ITERATOR_HELPER.n()).done;) BODY;
} catch (err) {
ITERATOR_HELPER.e(err);
} finally {
ITERATOR_HELPER.f();
}
`);

const builder = loose
? {
build: buildForOfLoose,
helper: "createForOfIteratorHelperLoose",
getContainer: nodes => nodes,
}
: {
build: buildForOf,
helper: "createForOfIteratorHelper",
getContainer: nodes => nodes[1].block.body,
};

function _ForOfStatementArray(path) {
const { node, scope } = path;

const right = scope.generateUidIdentifierBasedOnNode(node.right, "arr");
const iterationKey = scope.generateUidIdentifier("i");

let loop = buildForOfArray({
const loop = buildForOfArray({
BODY: node.body,
KEY: iterationKey,
NAME: right,
Expand Down Expand Up @@ -137,19 +145,7 @@ export default declare((api, options) => {
);
}

if (path.parentPath.isLabeledStatement()) {
loop = t.labeledStatement(path.parentPath.node.label, loop);
}

return [loop];
}

function replaceWithArray(path) {
if (path.parentPath.isLabeledStatement()) {
path.parentPath.replaceWithMultiple(_ForOfStatementArray(path));
} else {
path.replaceWithMultiple(_ForOfStatementArray(path));
}
return loop;
}

return {
Expand All @@ -162,149 +158,68 @@ export default declare((api, options) => {
right.isGenericType("Array") ||
t.isArrayTypeAnnotation(right.getTypeAnnotation())
) {
replaceWithArray(path);
path.replaceWith(_ForOfStatementArray(path));
return;
}

const { node } = path;
const build = pushComputedProps(path, state);
const declar = build.declar;
const loop = build.loop;
const block = loop.body;
const { node, parent, scope } = path;
const left = node.left;
let declar;

const stepKey = scope.generateUid("step");
const stepValue = t.memberExpression(
t.identifier(stepKey),
t.identifier("value"),
);

if (
t.isIdentifier(left) ||
t.isPattern(left) ||
t.isMemberExpression(left)
) {
// for (i of test), for ({ i } of test)
declar = t.expressionStatement(
t.assignmentExpression("=", left, stepValue),
);
} else if (t.isVariableDeclaration(left)) {
// for (let i of test)
declar = t.variableDeclaration(left.kind, [
t.variableDeclarator(left.declarations[0].id, stepValue),
]);
} else {
throw path
.get("left")
.buildCodeFrameError(
`Unknown node type ${left.type} in ForStatement`,
);
}

// ensure that it's a block so we can take all its statements
path.ensureBlock();

// add the value declaration to the new loop body
if (declar) {
block.body.push(declar);
}
node.body.body.unshift(declar);

const nodes = builder.build({
CREATE_ITERATOR_HELPER: state.addHelper(builder.helper),
ITERATOR_HELPER: scope.generateUidIdentifier("iteratorHelper"),
STEP_KEY: t.identifier(stepKey),
OBJECT: node.right,
BODY: node.body,
});
const container = builder.getContainer(nodes);

// push the rest of the original loop body onto our new body
block.body = block.body.concat(node.body.body);
t.inherits(container[0], node);
t.inherits(container[0].body, node.body);

t.inherits(loop, node);
t.inherits(loop.body, node.body);
if (t.isLabeledStatement(parent)) {
container[0] = t.labeledStatement(parent.label, container[0]);

if (build.replaceParent) {
path.parentPath.replaceWithMultiple(build.node);
path.parentPath.replaceWithMultiple(nodes);
path.remove();
} else {
path.replaceWithMultiple(build.node);
path.replaceWithMultiple(nodes);
}
},
},
};

function pushComputedPropsLoose(path, file) {
const { node, scope, parent } = path;
const left = node.left;
let declar;

const stepKey = scope.generateUid("step");
const stepValue = t.memberExpression(
t.identifier(stepKey),
t.identifier("value"),
);

if (
t.isIdentifier(left) ||
t.isPattern(left) ||
t.isMemberExpression(left)
) {
// for (i of test), for ({ i } of test)
declar = t.expressionStatement(
t.assignmentExpression("=", left, stepValue),
);
} else if (t.isVariableDeclaration(left)) {
// for (let i of test)
declar = t.variableDeclaration(left.kind, [
t.variableDeclarator(left.declarations[0].id, stepValue),
]);
} else {
throw file.buildCodeFrameError(
left,
`Unknown node type ${left.type} in ForStatement`,
);
}

const template = buildForOfLoose({
CREATE_ITERATOR_HELPER: file.addHelper("createForOfIteratorHelperLoose"),
ITERATOR_HELPER: scope.generateUidIdentifier("iteratorHelper"),
STEP_KEY: t.identifier(stepKey),
OBJECT: node.right,
});
const loop = template[0];

const isLabeledParent = t.isLabeledStatement(parent);

if (isLabeledParent) {
template[0] = t.labeledStatement(parent.label, loop);
}

return {
replaceParent: isLabeledParent,
declar,
loop,
node: template,
};
}

function pushComputedPropsSpec(path, file) {
const { node, scope, parent } = path;
const left = node.left;
let declar;

const stepKey = scope.generateUid("step");
const stepValue = t.memberExpression(
t.identifier(stepKey),
t.identifier("value"),
);

if (
t.isIdentifier(left) ||
t.isPattern(left) ||
t.isMemberExpression(left)
) {
// for (i of test), for ({ i } of test)
declar = t.expressionStatement(
t.assignmentExpression("=", left, stepValue),
);
} else if (t.isVariableDeclaration(left)) {
// for (let i of test)
declar = t.variableDeclaration(left.kind, [
t.variableDeclarator(left.declarations[0].id, stepValue),
]);
} else {
throw file.buildCodeFrameError(
left,
`Unknown node type ${left.type} in ForStatement`,
);
}

const template = buildForOf({
CREATE_ITERATOR_HELPER: file.addHelper("createForOfIteratorHelper"),
ITERATOR_HELPER: scope.generateUidIdentifier("iteratorHelper"),
STEP_KEY: t.identifier(stepKey),
OBJECT: node.right,
});

const isLabeledParent = t.isLabeledStatement(parent);

const tryBody = template[1].block.body;
const loop = tryBody[0];

if (isLabeledParent) {
tryBody[0] = t.labeledStatement(parent.label, loop);
}

//

return {
replaceParent: isLabeledParent,
declar: declar,
loop: loop,
node: template,
};
}
});
6 changes: 2 additions & 4 deletions packages/babel-plugin-transform-for-of/test/fixtures/regression/if-label-3858/output.js
View file
@@ -1,5 +1,3 @@
if (true) {
loop: for (var _i = 0, _arr = []; _i < _arr.length; _i++) {
let ch = _arr[_i];
}
if (true) loop: for (var _i = 0, _arr = []; _i < _arr.length; _i++) {
let ch = _arr[_i];
}

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