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function makeArray(array) {
var log = [];
Object.setPrototypeOf(array, new Proxy(Array.prototype, new Proxy({
has(t, pk) {
log.push(`Has:${String(pk)}`);
return Reflect.has(t, pk);
},
}, {
get(t, pk, r) {
if (pk in t)
return Reflect.get(t, pk, r);
throw new Error(`Unexpected trap "${pk}" called`);
}
})));
return {array, log};
}
var {array, log} = makeArray([1, null, 3]);
Array.prototype.indexOf.call(array, 100, {
valueOf() {
array.length = 0;
return 0;
}
});
assertEqArray(log, ["Has:0", "Has:1", "Has:2"]);
var {array, log} = makeArray([5, undefined, 7]);
Array.prototype.lastIndexOf.call(array, 100, {
valueOf() {
array.length = 0;
return 2;
}
});
assertEqArray(log, ["Has:2", "Has:1", "Has:0"]);
if (typeof reportCompare === "function")
reportCompare(true, true);
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