json-schema-to-typescript/dist/src/memoize.js

compile json schema to typescript typings

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.memoize = memoize;
/**
 * Memoizes a function on its first argument, which must be an object.
 *
 * lodash's `memoize` backs its cache with a native `Map`, but only if it can
 * convince itself that `Map` is native: it builds a regex out of
 * `Function.prototype.toString.call(Object.prototype.hasOwnProperty)` and tests
 * `Map`'s source against it. Bun prints the two in different shapes --
 * `hasOwnProperty` over three lines, `Map` on one -- so the check fails and the
 * cache degrades to a list that is scanned linearly on every read. Compiling a
 * large schema goes from seconds to minutes. (`Set`, `WeakMap` and `DataView`
 * fail the same check, so lodash's `Stack`, and therefore `cloneDeep`, is
 * slower under bun too.)
 *
 * A `WeakMap` is what we want here anyway: keys are schema/AST nodes, and the
 * cache should die with them.
 *
 * Like lodash, only the first argument takes part in the cache key.
 */
function memoize(fn) {
    const cache = new WeakMap();
    return (a, ...rest) => {
        if (cache.has(a)) {
            return cache.get(a);
        }
        const result = fn(a, ...rest);
        cache.set(a, result);
        return result;
    };
}
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