then-interception.any.js (1750B)
1 // META: global=window,worker,shadowrealm 2 // META: script=../resources/test-utils.js 3 // META: script=../resources/recording-streams.js 4 'use strict'; 5 6 function interceptThen() { 7 const intercepted = []; 8 let callCount = 0; 9 Object.prototype.then = function(resolver) { 10 if (!this.done) { 11 intercepted.push(this.value); 12 } 13 const retval = Object.create(null); 14 retval.done = ++callCount === 3; 15 retval.value = callCount; 16 resolver(retval); 17 if (retval.done) { 18 delete Object.prototype.then; 19 } 20 } 21 return intercepted; 22 } 23 24 promise_test(async t => { 25 const rs = new ReadableStream({ 26 start(controller) { 27 controller.enqueue('a'); 28 controller.close(); 29 } 30 }); 31 const ws = recordingWritableStream(); 32 33 const intercepted = interceptThen(); 34 t.add_cleanup(() => { 35 delete Object.prototype.then; 36 }); 37 38 await rs.pipeTo(ws); 39 delete Object.prototype.then; 40 41 42 assert_array_equals(intercepted, [], 'nothing should have been intercepted'); 43 assert_array_equals(ws.events, ['write', 'a', 'close'], 'written chunk should be "a"'); 44 }, 'piping should not be observable'); 45 46 promise_test(async t => { 47 const rs = new ReadableStream({ 48 start(controller) { 49 controller.enqueue('a'); 50 controller.close(); 51 } 52 }); 53 const ws = recordingWritableStream(); 54 55 const [ branch1, branch2 ] = rs.tee(); 56 57 const intercepted = interceptThen(); 58 t.add_cleanup(() => { 59 delete Object.prototype.then; 60 }); 61 62 await branch1.pipeTo(ws); 63 delete Object.prototype.then; 64 branch2.cancel(); 65 66 assert_array_equals(intercepted, [], 'nothing should have been intercepted'); 67 assert_array_equals(ws.events, ['write', 'a', 'close'], 'written chunk should be "a"'); 68 }, 'tee should not be observable');