forked from babel/babel
/
index.js
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/
index.js
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export default function ({ messages, template, types: t }) {
const buildForOfArray = template(`
for (var KEY = 0; KEY < ARR.length; KEY++) BODY;
`);
const buildForOfLoose = template(`
for (var LOOP_OBJECT = OBJECT,
IS_ARRAY = Array.isArray(LOOP_OBJECT),
INDEX = 0,
LOOP_OBJECT = IS_ARRAY ? LOOP_OBJECT : LOOP_OBJECT[Symbol.iterator]();;) {
var ID;
if (IS_ARRAY) {
if (INDEX >= LOOP_OBJECT.length) break;
ID = LOOP_OBJECT[INDEX++];
} else {
INDEX = LOOP_OBJECT.next();
if (INDEX.done) break;
ID = INDEX.value;
}
}
`);
/* eslint-disable max-len */
const buildForOf = template(`
var ITERATOR_COMPLETION = true;
var ITERATOR_HAD_ERROR_KEY = false;
var ITERATOR_ERROR_KEY = undefined;
try {
for (var ITERATOR_KEY = OBJECT[Symbol.iterator](), STEP_KEY; !(ITERATOR_COMPLETION = (STEP_KEY = ITERATOR_KEY.next()).done); ITERATOR_COMPLETION = true) {
}
} catch (err) {
ITERATOR_HAD_ERROR_KEY = true;
ITERATOR_ERROR_KEY = err;
} finally {
try {
if (!ITERATOR_COMPLETION && ITERATOR_KEY.return) {
ITERATOR_KEY.return();
}
} finally {
if (ITERATOR_HAD_ERROR_KEY) {
throw ITERATOR_ERROR_KEY;
}
}
}
`);
/* eslint-enable max-len */
function _ForOfStatementArray(path) {
const { node, scope } = path;
const nodes = [];
let right = node.right;
if (!t.isIdentifier(right) || !scope.hasBinding(right.name)) {
const uid = scope.generateUidIdentifier("arr");
nodes.push(t.variableDeclaration("var", [
t.variableDeclarator(uid, right),
]));
right = uid;
}
const iterationKey = scope.generateUidIdentifier("i");
let loop = buildForOfArray({
BODY: node.body,
KEY: iterationKey,
ARR: right,
});
t.inherits(loop, node);
t.ensureBlock(loop);
const iterationValue = t.memberExpression(right, iterationKey, true);
const left = node.left;
if (t.isVariableDeclaration(left)) {
left.declarations[0].init = iterationValue;
loop.body.body.unshift(left);
} else {
loop.body.body.unshift(t.expressionStatement(
t.assignmentExpression("=", left, iterationValue)));
}
if (path.parentPath.isLabeledStatement()) {
loop = t.labeledStatement(path.parentPath.node.label, loop);
}
nodes.push(loop);
return nodes;
}
return {
visitor: {
ForOfStatement(path, state) {
if (path.get("right").isArrayExpression()) {
if (path.parentPath.isLabeledStatement()) {
path.parentPath.replaceWithMultiple(_ForOfStatementArray(path));
return;
} else {
path.replaceWithMultiple(_ForOfStatementArray(path));
return;
}
}
let callback = spec;
if (state.opts.loose) callback = loose;
const { node } = path;
const build = callback(path, state);
const declar = build.declar;
const loop = build.loop;
const block = loop.body;
// 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);
}
// push the rest of the original loop body onto our new body
block.body = block.body.concat(node.body.body);
t.inherits(loop, node);
t.inherits(loop.body, node.body);
if (build.replaceParent) {
path.parentPath.replaceWithMultiple(build.node);
path.remove();
} else {
path.replaceWithMultiple(build.node);
}
},
},
};
function loose(path, file) {
const { node, scope, parent } = path;
const { left } = node;
let declar, id;
if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
// for (i of test), for ({ i } of test)
id = left;
} else if (t.isVariableDeclaration(left)) {
// for (let i of test)
id = scope.generateUidIdentifier("ref");
declar = t.variableDeclaration(left.kind, [
t.variableDeclarator(left.declarations[0].id, id),
]);
} else {
throw file.buildCodeFrameError(left, messages.get("unknownForHead", left.type));
}
const iteratorKey = scope.generateUidIdentifier("iterator");
const isArrayKey = scope.generateUidIdentifier("isArray");
const loop = buildForOfLoose({
LOOP_OBJECT: iteratorKey,
IS_ARRAY: isArrayKey,
OBJECT: node.right,
INDEX: scope.generateUidIdentifier("i"),
ID: id,
});
if (!declar) {
// no declaration so we need to remove the variable declaration at the top of
// the for-of-loose template
loop.body.body.shift();
}
//
const isLabeledParent = t.isLabeledStatement(parent);
let labeled;
if (isLabeledParent) {
labeled = t.labeledStatement(parent.label, loop);
}
return {
replaceParent: isLabeledParent,
declar: declar,
node: labeled || loop,
loop: loop,
};
}
function spec(path, file) {
const { node, scope, parent } = path;
const left = node.left;
let declar;
const stepKey = scope.generateUidIdentifier("step");
const stepValue = t.memberExpression(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, messages.get("unknownForHead", left.type));
}
//
const iteratorKey = scope.generateUidIdentifier("iterator");
const template = buildForOf({
ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
ITERATOR_COMPLETION: scope.generateUidIdentifier("iteratorNormalCompletion"),
ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
ITERATOR_KEY: iteratorKey,
STEP_KEY: stepKey,
OBJECT: node.right,
BODY: null,
});
const isLabeledParent = t.isLabeledStatement(parent);
const tryBody = template[3].block.body;
const loop = tryBody[0];
if (isLabeledParent) {
tryBody[0] = t.labeledStatement(parent.label, loop);
}
//
return {
replaceParent: isLabeledParent,
declar: declar,
loop: loop,
node: template,
};
}
}