safe-push-apply

var safePushApply = require('safe-push-apply');
var assert = require('assert');

var arr = [1, 2, 3];

var orig = Array.prototype[Symbol.iterator];
delete Array.prototype[Symbol.iterator];
assert.throws(() => {
    try {
        arr.push(...[3, 4, 5]);
    } finally {
        Array.prototype[Symbol.iterator] = orig;
    }
}, 'array is not iterable anymore');

delete Array.prototype.push;
safePushApply(arr, [3, 4, 5]);

assert.deepEqual(arr, [1, 2, 3, 3, 4, 5]);