test_array_sparse_descending_length.cjs
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test_array_sparse_descending_length.cjs
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	const assert = require("node:assert");

	const arr = [];
	for (let n = 128, i = 0; i < 111; i++) {
	arr[--n] = i;
	}

	assert.equal(arr.length, 128);
	assert.equal(arr[127], 0);
	assert.equal(arr[31], 96);
	assert.equal(arr[30], 97);
	assert.equal(arr[17], 110);
	assert.equal(arr[16], undefined);
	assert.equal(Object.keys(arr).length, 111);

	const mixed = [];
	mixed[127] = "tail";
	mixed[31] = "lower";

	assert.equal(mixed.length, 128);
	assert.equal(mixed[127], "tail");
	assert.equal(mixed[31], "lower");

	console.log("OK: sparse descending array writes preserve length");