symbols.js - mozsearch

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/* Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/licenses/publicdomain/ */

load(libdir + "asserts.js");

var s = new Set;

// Symbols can be stored in Sets.

var sym = Symbol();

s.add(sym);

assertEq(s.has(sym), true);

assertEq(s.has(Symbol()), false);

assertEq([...s][0], sym);

s.add(sym);

assertEq(s.has(sym), true);

assertEq(s.size, 1);

s.delete(sym);

assertEq(s.has(sym), false);

assertEq(s.size, 0);

// Symbols returned by Symbol.for() can be in Sets.

var str = "how much wood would a woodchuck chuck if a woodchuck could chuck wood";

var s2  = "how much wood would a woodchuck chuck if could";

var arr = str.split(" ").map(Symbol.for);

s = new Set(arr);

assertDeepEq([...s], s2.split(" ").map(Symbol.for));