babel-plugin-recursive-tail-calls/dist/tailRecursionFinder.js

A babel plugin for performing tail call optimization in recursive functions.

import { isRecCall } from "./utils.js";
/**
 * Babel visitor to find tail recursion in `ReturnStatement`s.
 * Descends down `LogicalExpression`s and `ConditionalExpression`s
 * to find recursive calls in tail position.
 * Sets `found` on state to `true` if recursion is found.
 */
export const tailRecursionFinder = {
    enter(path) {
        if (path.isCallExpression()) {
            this.found = isRecCall(path, this.functionIdentifier);
            if (this.found)
                path.stop();
        }
        else if (path.isLogicalExpression())
            path.skipKey("left");
        else if (path.isConditionalExpression())
            path.skipKey("test");
        else
            path.skip();
    },
};
/**
 * Use `tailRecursionFinder` to look for calls to `functionIdentifier` in `path`.
 */
export function findRecursion(path, functionIdentifier) {
    const state = {
        found: false,
        functionIdentifier,
    };
    // traverse omits the current node, traverse parent instead
    path.parentPath.traverse(tailRecursionFinder, state);
    return state.found;
}