Promise در جاوا اسکریپت و کاربردهای آن — به زبان ساده

1var keepsHisWord;
2keepsHisWord = true;
3promise1 = new Promise(function(resolve, reject) {
4  if (keepsHisWord) {
5    resolve("The man likes to keep his word");
6  } else {
7    reject("The man doesnt want to keep his word");
8  }
9});
10console.log(promise1);

1promise2 = new Promise(function(resolve, reject) {
2  setTimeout(function() {
3    resolve({
4      message: "The man likes to keep his word",
5      code: "aManKeepsHisWord"
6    });
7  }, 10 * 1000);
8});
9console.log(promise2);

1keepsHisWord = false;
2promise3 = new Promise(function(resolve, reject) {
3  if (keepsHisWord) {
4    resolve("The man likes to keep his word");
5  } else {
6    reject("The man doesn't want to keep his word");
7  }
8});
9console.log(promise3);

1var momsPromise = new Promise(function(resolve, reject) {
2  momsSavings = 20000;
3  priceOfPhone = 60000;
4  if (momsSavings > priceOfPhone) {
5    resolve({
6      brand: "iphone",
7      model: "6s"
8    });
9  } else {
10    reject("We donot have enough savings. Let us save some more money.");
11  }
12});
13momsPromise.then(function(value) {
14  console.log("Hurray I got this phone as a gift ", JSON.stringify(value));
15});
16momsPromise.catch(function(reason) {
17  console.log("Mom coudn't buy me the phone because ", reason);
18});
19momsPromise.finally(function() {
20  console.log(
21    "Irrespecitve of whether my mom can buy me a phone or not, I still love her"
22  );
23});

1momsPromise.then(
2  function(value) {
3    console.log("Hurray I got this phone as a gift ", JSON.stringify(value));
4  },
5  function(reason) {
6    console.log("Mom coudn't buy me the phone because ", reason);
7  }
8);

1function getRandomNumber(start = 1, end = 10) {
2  //works when both start,end are >=1 and end > start
3  return parseInt(Math.random() * end) % (end-start+1) + start;
4}

1function getRandomNumber(start = 1, end = 10) {
2  //works when both start and end are >=1
3  return (parseInt(Math.random() * end) % (end - start + 1)) + start;
4}
5var promiseTRRARNOSG = (promiseThatResolvesRandomlyAfterRandomNumnberOfSecondsGenerator = function() {
6  return new Promise(function(resolve, reject) {
7    let randomNumberOfSeconds = getRandomNumber(2, 10);
8    setTimeout(function() {
9      let randomiseResolving = getRandomNumber(1, 10);
10      if (randomiseResolving > 5) {
11        resolve({
12          randomNumberOfSeconds: randomNumberOfSeconds,
13          randomiseResolving: randomiseResolving
14        });
15      } else {
16        reject({
17          randomNumberOfSeconds: randomNumberOfSeconds,
18          randomiseResolving: randomiseResolving
19        });
20      }
21    }, randomNumberOfSeconds * 1000);
22  });
23});
24var testProimse = promiseTRRARNOSG();
25testProimse.then(function(value) {
26  console.log("Value when promise is resolved : ", value);
27});
28testProimse.catch(function(reason) {
29  console.log("Reason when promise is rejected : ", reason);
30});
31// Let us loop through and create ten different promises using the function to see some variation. Some will be resolved and some will be rejected. 
32for (i=1; i<=10; i++) {
33  let promise = promiseTRRARNOSG();
34  promise.then(function(value) {
35    console.log("Value when promise is resolved : ", value);
36  });
37  promise.catch(function(reason) {
38    console.log("Reason when promise is rejected : ", reason);
39  });
40}

1Promise.reject(reason)

1var promise3 = Promise.reject("Not interested");
2promise3.then(function(value){
3  console.log("This will not run as it is a resolved promise. The resolved value is ", value);
4});
5promise3.catch(function(reason){
6  console.log("This run as it is a rejected promise. The reason is ", reason);
7});

1Promise.resolve(value)

1var promise4 = Promise.resolve(1);
2promise4.then(function(value){
3  console.log("This will run as it is a resovled promise. The resolved value is ", value);
4});
5promise4.catch(function(reason){
6  console.log("This will not run as it is a resolved promise", reason);
7});

1var promise4 = Promise.resolve(1);
2promise4.then(function(value){
3  console.log("This will run as it is a resovled promise. The resolved value is ", value);
4});
5promise4.then(function(value){
6  console.log("This will also run as multiple handlers can be added. Printing twice the resolved value which is ", value * 2);
7});
8promise4.catch(function(reason){
9  console.log("This will not run as it is a resolved promise", reason);
10});

1var promiseTRSANSG = (promiseThatResolvesAfterNSecondsGenerator = function(
2  n = 0
3) {
4  return new Promise(function(resolve, reject) {
5    setTimeout(function() {
6      resolve({
7        resolvedAfterNSeconds: n
8      });
9    }, n * 1000);
10  });
11});
12var promiseTRJANSG = (promiseThatRejectsAfterNSecondsGenerator = function(
13  n = 0
14) {
15  return new Promise(function(resolve, reject) {
16    setTimeout(function() {
17      reject({
18        rejectedAfterNSeconds: n
19      });
20    }, n * 1000);
21  });
22});

1console.time("Promise.All");
2var promisesArray = [];
3promisesArray.push(promiseTRSANSG(1));
4promisesArray.push(promiseTRSANSG(4));
5promisesArray.push(promiseTRSANSG(2));
6var handleAllPromises = Promise.all(promisesArray);
7handleAllPromises.then(function(values) {
8  console.timeEnd("Promise.All");
9  console.log("All the promises are resolved", values);
10});
11handleAllPromises.catch(function(reason) {
12  console.log("One of the promises failed with the following reason", reason);
13});

1console.time("Promise.All");
2var promisesArray = [];
3promisesArray.push(1);
4promisesArray.push(4);
5promisesArray.push(2);
6var handleAllPromises = Promise.all(promisesArray);
7handleAllPromises.then(function(values) {
8  console.timeEnd("Promise.All");
9  console.log("All the promises are resolved", values);
10});
11handleAllPromises.catch(function(reason) {
12  console.log("One of the promises failed with the following reason", reason);
13});

1console.time("Promise.All");
2var promisesArray = [];
3promisesArray.push(promiseTRSANSG(1));
4promisesArray.push(promiseTRSANSG(5));
5promisesArray.push(promiseTRSANSG(3));
6promisesArray.push(promiseTRJANSG(2));
7promisesArray.push(promiseTRSANSG(4));
8var handleAllPromises = Promise.all(promisesArray);
9handleAllPromises.then(function(values) {
10  console.timeEnd("Promise.All");
11  console.log("All the promises are resolved", values);
12});
13handleAllPromises.catch(function(reason) {
14  console.timeEnd("Promise.All");
15  console.log("One of the promises failed with the following reason ", reason);
16});

1console.time("Promise.race");
2var promisesArray = [];
3promisesArray.push(promiseTRSANSG(4));
4promisesArray.push(promiseTRSANSG(3));
5promisesArray.push(promiseTRSANSG(2));
6promisesArray.push(promiseTRJANSG(3));
7promisesArray.push(promiseTRSANSG(4));
8var promisesRace = Promise.race(promisesArray);
9promisesRace.then(function(values) {
10  console.timeEnd("Promise.race");
11  console.log("The fasted promise resolved", values);
12});
13promisesRace.catch(function(reason) {
14  console.timeEnd("Promise.race");
15  console.log("The fastest promise rejected with the following reason ", reason);
16});

1console.time("Promise.race");
2var promisesArray = [];
3promisesArray.push(promiseTRSANSG(4));
4promisesArray.push(promiseTRSANSG(6));
5promisesArray.push(promiseTRSANSG(5));
6promisesArray.push(promiseTRJANSG(3));
7promisesArray.push(promiseTRSANSG(4));
8var promisesRace = Promise.race(promisesArray);
9promisesRace.then(function(values) {
10  console.timeEnd("Promise.race");
11  console.log("The fasted promise resolved", values);
12});
13promisesRace.catch(function(reason) {
14  console.timeEnd("Promise.race");
15  console.log("The fastest promise rejected with the following reason ", reason);
16});

1var keepsHisWord;
2keepsHisWord = true;
3promise1 = new Promise(function(resolve, reject) {
4  if (keepsHisWord) {
5    resolve("The man likes to keep his word");
6  } else {
7    reject("The man doesnt want to keep his word");
8  }
9});
10console.log(promise1);
11
12promise2 = new Promise(function(resolve, reject) {
13  setTimeout(function() {
14    resolve({
15      message: "The man likes to keep his word",
16      code: "aManKeepsHisWord"
17    });
18  }, 10 * 1000);
19});
20console.log(promise2);
21
22keepsHisWord = false;
23promise3 = new Promise(function(resolve, reject) {
24  if (keepsHisWord) {
25    resolve("The man likes to keep his word");
26  } else {
27    reject("The man doesn't want to keep his word");
28  }
29});
30console.log(promise3);
31
32var momsPromise = new Promise(function(resolve, reject) {
33  momsSavings = 20000;
34  priceOfPhone = 60000;
35  if (momsSavings > priceOfPhone) {
36    resolve({
37      brand: "iphone",
38      model: "6s"
39    });
40  } else {
41    reject("We donot have enough savings. Let us save some more money.");
42  }
43});
44momsPromise.then(function(value) {
45  console.log("Hurray I got this phone as a gift ", JSON.stringify(value));
46});
47momsPromise.catch(function(reason) {
48  console.log("Mom coudn't buy me the phone because ", reason);
49});
50momsPromise.finally(function() {
51  console.log(
52    "Irrespecitve of whether my mom can buy me a phone or not, I still love her"
53  );
54});
55
56momsPromise.then(
57  function(value) {
58    console.log("Hurray I got this phone as a gift ", JSON.stringify(value));
59  },
60  function(reason) {
61    console.log("Mom coudn't buy me the phone because ", reason);
62  }
63);
64
65function getRandomNumber(start = 1, end = 10) {
66  //works when both start,end are >=1 and end > start
67  return parseInt(Math.random() * end) % (end-start+1) + start;
68}
69
70function getRandomNumber(start = 1, end = 10) {
71  //works when both start and end are >=1
72  return (parseInt(Math.random() * end) % (end - start + 1)) + start;
73}
74var promiseTRRARNOSG = (promiseThatResolvesRandomlyAfterRandomNumnberOfSecondsGenerator = function() {
75  return new Promise(function(resolve, reject) {
76    let randomNumberOfSeconds = getRandomNumber(2, 10);
77    setTimeout(function() {
78      let randomiseResolving = getRandomNumber(1, 10);
79      if (randomiseResolving > 5) {
80        resolve({
81          randomNumberOfSeconds: randomNumberOfSeconds,
82          randomiseResolving: randomiseResolving
83        });
84      } else {
85        reject({
86          randomNumberOfSeconds: randomNumberOfSeconds,
87          randomiseResolving: randomiseResolving
88        });
89      }
90    }, randomNumberOfSeconds * 1000);
91  });
92});
93var testProimse = promiseTRRARNOSG();
94testProimse.then(function(value) {
95  console.log("Value when promise is resolved : ", value);
96});
97testProimse.catch(function(reason) {
98  console.log("Reason when promise is rejected : ", reason);
99});
100// Let us loop through and create ten different promises using the function to see some variation. Some will be resolved and some will be rejected. 
101for (i=1; i<=10; i++) {
102  let promise = promiseTRRARNOSG();
103  promise.then(function(value) {
104    console.log("Value when promise is resolved : ", value);
105  });
106  promise.catch(function(reason) {
107    console.log("Reason when promise is rejected : ", reason);
108  });
109}
110
111var promise3 = Promise.reject("Not interested");
112promise3.then(function(value){
113  console.log("This will not run as it is a resolved promise. The resolved value is ", value);
114});
115promise3.catch(function(reason){
116  console.log("This run as it is a rejected promise. The reason is ", reason);
117});
118
119var promise4 = Promise.resolve(1);
120promise4.then(function(value){
121  console.log("This will run as it is a resovled promise. The resolved value is ", value);
122});
123promise4.catch(function(reason){
124  console.log("This will not run as it is a resolved promise", reason);
125});
126
127
128var promise4 = Promise.resolve(1);
129promise4.then(function(value){
130  console.log("This will run as it is a resovled promise. The resolved value is ", value);
131});
132promise4.then(function(value){
133  console.log("This will also run as multiple handlers can be added. Printing twice the resolved value which is ", value * 2);
134});
135promise4.catch(function(reason){
136  console.log("This will not run as it is a resolved promise", reason);
137});
138
139
140var promiseTRSANSG = (promiseThatResolvesAfterNSecondsGenerator = function(
141  n = 0
142) {
143  return new Promise(function(resolve, reject) {
144    setTimeout(function() {
145      resolve({
146        resolvedAfterNSeconds: n
147      });
148    }, n * 1000);
149  });
150});
151var promiseTRJANSG = (promiseThatRejectsAfterNSecondsGenerator = function(
152  n = 0
153) {
154  return new Promise(function(resolve, reject) {
155    setTimeout(function() {
156      reject({
157        rejectedAfterNSeconds: n
158      });
159    }, n * 1000);
160  });
161});
162
163console.time("Promise.All");
164var promisesArray = [];
165promisesArray.push(promiseTRSANSG(1));
166promisesArray.push(promiseTRSANSG(4));
167promisesArray.push(promiseTRSANSG(2));
168var handleAllPromises = Promise.all(promisesArray);
169handleAllPromises.then(function(values) {
170  console.timeEnd("Promise.All");
171  console.log("All the promises are resolved", values);
172});
173handleAllPromises.catch(function(reason) {
174  console.log("One of the promises failed with the following reason", reason);
175});
176
177console.time("Promise.All");
178var promisesArray = [];
179promisesArray.push(1);
180promisesArray.push(4);
181promisesArray.push(2);
182var handleAllPromises = Promise.all(promisesArray);
183handleAllPromises.then(function(values) {
184  console.timeEnd("Promise.All");
185  console.log("All the promises are resolved", values);
186});
187handleAllPromises.catch(function(reason) {
188  console.log("One of the promises failed with the following reason", reason);
189});
190
191
192console.time("Promise.All");
193var promisesArray = [];
194promisesArray.push(promiseTRSANSG(1));
195promisesArray.push(promiseTRSANSG(5));
196promisesArray.push(promiseTRSANSG(3));
197promisesArray.push(promiseTRJANSG(2));
198promisesArray.push(promiseTRSANSG(4));
199var handleAllPromises = Promise.all(promisesArray);
200handleAllPromises.then(function(values) {
201  console.timeEnd("Promise.All");
202  console.log("All the promises are resolved", values);
203});
204handleAllPromises.catch(function(reason) {
205  console.timeEnd("Promise.All");
206  console.log("One of the promises failed with the following reason ", reason);
207});
208
209
210console.time("Promise.race");
211var promisesArray = [];
212promisesArray.push(promiseTRSANSG(4));
213promisesArray.push(promiseTRSANSG(3));
214promisesArray.push(promiseTRSANSG(2));
215promisesArray.push(promiseTRJANSG(3));
216promisesArray.push(promiseTRSANSG(4));
217var promisesRace = Promise.race(promisesArray);
218promisesRace.then(function(values) {
219  console.timeEnd("Promise.race");
220  console.log("The fasted promise resolved", values);
221});
222promisesRace.catch(function(reason) {
223  console.timeEnd("Promise.race");
224  console.log("The fastest promise rejected with the following reason ", reason);
225});
226
227
228console.time("Promise.race");
229var promisesArray = [];
230promisesArray.push(promiseTRSANSG(4));
231promisesArray.push(promiseTRSANSG(6));
232promisesArray.push(promiseTRSANSG(5));
233promisesArray.push(promiseTRJANSG(3));
234promisesArray.push(promiseTRSANSG(4));
235var promisesRace = Promise.race(promisesArray);
236promisesRace.then(function(values) {
237  console.timeEnd("Promise.race");
238  console.log("The fasted promise resolved", values);
239});
240promisesRace.catch(function(reason) {
241  console.timeEnd("Promise.race");
242  console.log("The fastest promise rejected with the following reason ", reason);
243});