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Fix bug incorrect dereferencing rest argument (#5810)

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* Fix bug incorrect dereferencing rest argument

* Fix pure path

* Minor refactor
This commit is contained in:
Buu Nguyen
2017-07-11 20:26:57 -07:00
committed by Henry Zhu
parent 650cd43096
commit 8decefe8bc
6 changed files with 56 additions and 10 deletions
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28
packages/babel-plugin-transform-es2015-parameters/src/rest.js
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@@ -12,11 +12,11 @@ const buildRest = template(`
`);
const restIndex = template(`
ARGUMENTS.length <= INDEX ? undefined : ARGUMENTS[INDEX]
(INDEX < OFFSET || ARGUMENTS.length <= INDEX) ? undefined : ARGUMENTS[INDEX]
`);
const restIndexImpure = template(`
REF = INDEX, ARGUMENTS.length <= REF ? undefined : ARGUMENTS[REF]
REF = INDEX, (REF < OFFSET || ARGUMENTS.length <= REF) ? undefined : ARGUMENTS[REF]
`);
const restLength = template(`
@@ -159,6 +159,7 @@ function hasRest(node) {
}
function optimiseIndexGetter(path, argsId, offset) {
const offsetLiteral = t.numericLiteral(offset);
let index;
if (t.isNumericLiteral(path.parent.property)) {
@@ -167,11 +168,7 @@ function optimiseIndexGetter(path, argsId, offset) {
// Avoid unnecessary '+ 0'
index = path.parent.property;
} else {
index = t.binaryExpression(
"+",
path.parent.property,
t.numericLiteral(offset),
);
index = t.binaryExpression("+", path.parent.property, offsetLiteral);
}
const { scope } = path;
@@ -181,17 +178,32 @@ function optimiseIndexGetter(path, argsId, offset) {
path.parentPath.replaceWith(
restIndexImpure({
ARGUMENTS: argsId,
OFFSET: offsetLiteral,
INDEX: index,
REF: temp,
}),
);
} else {
path.parentPath.replaceWith(
const parentPath = path.parentPath;
parentPath.replaceWith(
restIndex({
ARGUMENTS: argsId,
OFFSET: offsetLiteral,
INDEX: index,
}),
);
// See if we can statically evaluate the first test (i.e. index < offset)
// and optimize the AST accordingly.
const offsetTestPath = parentPath.get("test").get("left");
const valRes = offsetTestPath.evaluate();
if (valRes.confident) {
if (valRes.value === true) {
parentPath.replaceWith(parentPath.scope.buildUndefinedNode());
} else {
parentPath.get("test").replaceWith(parentPath.get("test").get("right"));
}
}
}
}