build: Add some required modules for node

1 files changed, 55 insertions, 0 deletions

diff --git a/node_modules/mem/index.js b/node_modules/mem/index.js
new file mode 100644
index 0000000..aa5a073
--- /dev/null
+++ b/node_modules/mem/index.js
@@ -0,0 +1,55 @@
+'use strict';
+const mimicFn = require('mimic-fn');
+
+const cacheStore = new WeakMap();
+
+const defaultCacheKey = function (x) {
+	if (arguments.length === 1 && (x === null || x === undefined || (typeof x !== 'function' && typeof x !== 'object'))) {
+		return x;
+	}
+
+	return JSON.stringify(arguments);
+};
+
+module.exports = (fn, opts) => {
+	opts = Object.assign({
+		cacheKey: defaultCacheKey,
+		cache: new Map()
+	}, opts);
+
+	const memoized = function () {
+		const cache = cacheStore.get(memoized);
+		const key = opts.cacheKey.apply(null, arguments);
+
+		if (cache.has(key)) {
+			const c = cache.get(key);
+
+			if (typeof opts.maxAge !== 'number' || Date.now() < c.maxAge) {
+				return c.data;
+			}
+		}
+
+		const ret = fn.apply(null, arguments);
+
+		cache.set(key, {
+			data: ret,
+			maxAge: Date.now() + (opts.maxAge || 0)
+		});
+
+		return ret;
+	};
+
+	mimicFn(memoized, fn);
+
+	cacheStore.set(memoized, opts.cache);
+
+	return memoized;
+};
+
+module.exports.clear = fn => {
+	const cache = cacheStore.get(fn);
+
+	if (cache && typeof cache.clear === 'function') {
+		cache.clear();
+	}
+};