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heapstats.js
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heapstats.js
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// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
"use strict";
function allocTest(alloc, allocAssert, deallocAssert) {
// Helper func that GCs then returns memory usage
const sample = () => {
// deno-lint-ignore no-undef
gc();
return Deno.memoryUsage();
};
const delta = (t1, t2) => t2.heapUsed - t1.heapUsed;
// Sample "clean" heap usage
const t1 = sample();
// Alloc
let x = alloc();
const t2 = sample();
allocAssert(delta(t1, t2));
// Free
x = null;
const t3 = sample();
deallocAssert(delta(t2, t3));
}
function main() {
// Large-array test, 1M slot array consumes ~4MB (4B per slot)
allocTest(
() => new Array(1e6),
(delta) => console.log("Allocated:", Math.round(delta / 1e6) + "MB"),
(delta) => console.log("Freed:", Math.round(delta / 1e6) + "MB"),
);
}
main();