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Fix rest optimization errors.

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This commit is contained in:
Jesse McCarthy 2016-02-25 18:42:52 -05:00
parent 8419be1afc
commit 49e30f49bc
1 changed files with 49 additions and 30 deletions
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79
packages/babel-plugin-transform-es2015-parameters/src/rest.js
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@ -58,40 +58,59 @@ let memberExpressionOptimisationVisitor = {
state.deopted = true;
} else {
let {parentPath} = path;
let grandparentPath = parentPath.parentPath;
// ex: [rest[0]] = [rest[1]]
if (grandparentPath.isLVal()) {
state.deopted = true;
return;
}
// ex: `args[0]`
// ex: `args.whatever`
if (parentPath.isMemberExpression({ object: node })) {
let grandparentPath = parentPath.parentPath;
// ex: args[0]
if (
parentPath.isMemberExpression({ computed: true, object: node }) &&
let argsOptEligible = !state.deopted && !(
// ex: `args[0] = "whatever"`
(
grandparentPath.isAssignmentExpression() &&
parentPath.node === grandparentPath.node.left
) ||
// ex: `args[0] = "whatever"`
!(
grandparentPath.isAssignmentExpression() &&
parentPath.node === grandparentPath.node.left
) &&
!grandparentPath.isForInStatement()
) {
// if we know that this member expression is referencing a number then
// we can safely optimise it
let prop = parentPath.get("property");
if (prop.isBaseType("number")) {
state.candidates.push({cause: "indexGetter", path});
return;
}
}
// ex: `[args[0]] = ["whatever"]`
grandparentPath.isLVal() ||
// ex: args.length
if (parentPath.isMemberExpression({ computed: false, object: node })) {
let prop = parentPath.get("property");
if (prop.node.name === "length") {
state.candidates.push({cause: "lengthGetter", path});
return;
// ex: `for (rest[0] in this)`
// ex: `for (rest[0] of this)`
grandparentPath.isForXStatement() ||
// ex: `++args[0]`
// ex: `args[0]--`
grandparentPath.isUpdateExpression() ||
// ex: `delete args[0]`
grandparentPath.isUnaryExpression({ operator: "delete" }) ||
// ex: `args[0]()`
// ex: `new args[0]()`
// ex: `new args[0]`
(
(
grandparentPath.isCallExpression() ||
grandparentPath.isNewExpression()
) &&
parentPath.node === grandparentPath.node.callee
)
);
if (argsOptEligible) {
if (parentPath.node.computed) {
// if we know that this member expression is referencing a number then
// we can safely optimise it
if (parentPath.get("property").isBaseType("number")) {
state.candidates.push({cause: "indexGetter", path});
return;
}
}
// args.length
else if (parentPath.node.property.name === "length") {
state.candidates.push({cause: "lengthGetter", path});
return;
}
}
}