JSTests/microbenchmarks/string-prototype-split-observable-side-effects4.js

//@ runNoFTL

function assert(testedValue, msg) {
    if (!testedValue)
        throw Error(msg);
}

// RegExp.prototype with overridden exec: Testing ES6 21.2.5.11: 19.b. Let z be ? RegExpExec(splitter, S).
(function () {
    let accesses = [];
    let origDescriptor = Object.getOwnPropertyDescriptor(RegExp.prototype, "exec");
    let origExec = origDescriptor.value;

    let obj = /it/;
    Object.defineProperty(RegExp.prototype, "exec", {
        value: function(str) {
            accesses.push("exec");
            return origExec.call(this, str);
        }
    });

    // The @@split slow path should call an internal version of substr. Make sure that
    // it's not calling the public version which can be overridden.
    String.prototype.substr = function(start, length) {
        throw Error("Should not call overridden substr");
    }

    // The @@split slow path should only call the internal version of includes. Make sure
    // that it's not calling the public version which can be overridden.
    String.prototype.includes = function(pattern) {
        throw Error("Should not call overridden includes");
    }

    assert(accesses == "", "unexpected call to overridden props");
    let result = "splitme".split(obj);
    assert(accesses == "exec,exec,exec,exec,exec,exec", "Property accesses do not match expectation");
    assert(result == "spl,me", "Unexpected result");
})();