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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; state.deopted = true;
} else { } else {
let {parentPath} = path; let {parentPath} = path;
let grandparentPath = parentPath.parentPath;
// ex: [rest[0]] = [rest[1]] // ex: `args[0]`
if (grandparentPath.isLVal()) { // ex: `args.whatever`
state.deopted = true; if (parentPath.isMemberExpression({ object: node })) {
return; let grandparentPath = parentPath.parentPath;
}
// ex: args[0] let argsOptEligible = !state.deopted && !(
if ( // ex: `args[0] = "whatever"`
parentPath.isMemberExpression({ computed: true, object: node }) && (
grandparentPath.isAssignmentExpression() &&
parentPath.node === grandparentPath.node.left
) ||
// ex: `args[0] = "whatever"` // ex: `[args[0]] = ["whatever"]`
!( grandparentPath.isLVal() ||
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.length // ex: `for (rest[0] in this)`
if (parentPath.isMemberExpression({ computed: false, object: node })) { // ex: `for (rest[0] of this)`
let prop = parentPath.get("property"); grandparentPath.isForXStatement() ||
if (prop.node.name === "length") {
state.candidates.push({cause: "lengthGetter", path}); // ex: `++args[0]`
return; // 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;
}
} }
} }