tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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Object-apply-02.js (2025B)


      1 // tests calling native functions via Debugger.Object.prototype.apply/call
      2 
      3 load(libdir + "asserts.js");
      4 
      5 var g = newGlobal({newCompartment: true});
      6 g.eval("function f() { debugger; }");
      7 var dbg = new Debugger(g);
      8 
      9 function test(usingApply) {
     10    dbg.onDebuggerStatement = function (frame) {
     11        var max = frame.arguments[0];
     12        var cv = usingApply ? max.apply(null, [9, 16]) : max.call(null, 9, 16);
     13        assertEq(cv.return, 16);
     14 
     15        cv = usingApply ? max.apply() : max.call();
     16        assertEq(cv.return, -1/0);
     17 
     18        cv = usingApply ? max.apply(null, [2, 5, 3, 8, 1, 9, 4, 6, 7])
     19                        : max.call(null, 2, 5, 3, 8, 1, 9, 4, 6, 7);
     20        assertEq(cv.return, 9);
     21 
     22        // second argument to apply must be an array
     23        assertThrowsInstanceOf(function () { max.apply(null, 12); }, TypeError);
     24    };
     25    g.eval("f(Math.max);");
     26 
     27    dbg.onDebuggerStatement = function (frame) {
     28        var push = frame.arguments[0];
     29        var arr = frame.arguments[1];
     30        var cv;
     31 
     32        cv = usingApply ? push.apply(arr, [0, 1, 2]) : push.call(arr, 0, 1, 2);
     33        assertEq(cv.return, 3);
     34 
     35        cv = usingApply ? push.apply(arr, [arr]) : push.call(arr, arr);
     36        assertEq(cv.return, 4);
     37 
     38        cv = usingApply ? push.apply(arr) : push.call(arr);
     39        assertEq(cv.return, 4);
     40 
     41        // You can apply Array.prototype.push to a string; it does ToObject on
     42        // it.  But as the length property on String objects is non-writable,
     43        // attempting to increase the length will throw a TypeError.
     44        cv = usingApply
     45             ? push.apply("hello", ["world"])
     46             : push.call("hello", "world");
     47        assertEq("throw" in cv, true);
     48        var ex = cv.throw;
     49        assertEq(frame.evalWithBindings("ex instanceof TypeError", { ex: ex }).return, true);
     50    };
     51    g.eval("var a = []; f(Array.prototype.push, a);");
     52    assertEq(g.a.length, 4);
     53    assertEq(g.a.slice(0, 3).join(","), "0,1,2");
     54    assertEq(g.a[3], g.a);
     55 }
     56 
     57 test(true);
     58 test(false);