function bar(map, p) { return map.get(p) + map.get(p); } noInline(bar); function foo() { let map = new Map; let items = [ [10, 50], ["450", 78], [{}, {}], [Symbol(), true], [undefined, null], [true, null], [false, true], [45.87, {}] ]; for (let [key, value] of items) map.set(key, value); let start = Date.now(); for (let i = 0; i < 5000000; i++) bar(map, items[i % items.length][0]); const verbose = false; if (verbose) print(Date.now() - start); } foo();