63 lines
1.3 KiB
JavaScript
63 lines
1.3 KiB
JavaScript
import hoistVariables from "@babel/helper-hoist-variables";
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import type { NodePath } from "@babel/traverse";
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import * as t from "@babel/types";
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const visitor = {
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enter(path, state) {
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if (path.isThisExpression()) {
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state.foundThis = true;
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}
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if (path.isReferencedIdentifier({ name: "arguments" })) {
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state.foundArguments = true;
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}
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},
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Function(path) {
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path.skip();
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},
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};
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export default function(path: NodePath, scope = path.scope) {
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const { node } = path;
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const container = t.functionExpression(
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null,
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[],
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node.body,
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node.generator,
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node.async,
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);
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let callee = container;
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let args = [];
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// todo: only hoist if necessary
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hoistVariables(path, id => scope.push({ id }));
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const state = {
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foundThis: false,
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foundArguments: false,
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};
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path.traverse(visitor, state);
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if (state.foundArguments) {
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callee = t.memberExpression(container, t.identifier("apply"));
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args = [];
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if (state.foundThis) {
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args.push(t.thisExpression());
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}
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if (state.foundArguments) {
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if (!state.foundThis) args.push(t.nullLiteral());
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args.push(t.identifier("arguments"));
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}
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}
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let call = t.callExpression(callee, args);
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if (node.generator) call = t.yieldExpression(call, true);
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return t.returnStatement(call);
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}
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