/
no-helper-implementation.js
192 lines (166 loc) 路 5 KB
/
no-helper-implementation.js
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import { template, types as t } from "@babel/core";
// This is the legacy implementation, which inlines all the code.
// It must be kept for compatibility reasons.
// TODO (Babel 8): Remove this code.
export default function transformWithoutHelper(loose, path, state) {
const pushComputedProps = loose
? pushComputedPropsLoose
: pushComputedPropsSpec;
const { node } = path;
const build = pushComputedProps(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
Array.prototype.push.apply(block.body, 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);
}
}
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]();;) {
INTERMEDIATE;
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;
}
}
`);
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 != null) {
ITERATOR_KEY.return();
}
} finally {
if (ITERATOR_HAD_ERROR_KEY) {
throw ITERATOR_ERROR_KEY;
}
}
}
`);
function pushComputedPropsLoose(path, file) {
const { node, scope, parent } = path;
const { left } = node;
let declar, id, intermediate;
if (t.isIdentifier(left) || t.isPattern(left) || t.isMemberExpression(left)) {
// for (i of test), for ({ i } of test)
id = left;
intermediate = null;
} 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, t.identifier(id.name)),
]);
intermediate = t.variableDeclaration("var", [
t.variableDeclarator(t.identifier(id.name)),
]);
} else {
throw file.buildCodeFrameError(
left,
`Unknown node type ${left.type} in ForStatement`,
);
}
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,
INTERMEDIATE: intermediate,
});
//
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 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({
ITERATOR_HAD_ERROR_KEY: scope.generateUidIdentifier("didIteratorError"),
ITERATOR_COMPLETION: scope.generateUidIdentifier(
"iteratorNormalCompletion",
),
ITERATOR_ERROR_KEY: scope.generateUidIdentifier("iteratorError"),
ITERATOR_KEY: scope.generateUidIdentifier("iterator"),
STEP_KEY: t.identifier(stepKey),
OBJECT: node.right,
});
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,
};
}