Diferència entre revisions de la pàgina «Promises»
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| Línia 4: | Línia 4: | ||
=Exercises= | =Exercises= | ||
<ol> | <ol> | ||
| + | <li> | ||
| + | Create a form with 3 fields at the least | ||
| + | <!-- function validateForm(formData) { | ||
| + | return new Promise(function(resolve, reject) { | ||
| + | if (formData.username.length < 3) { | ||
| + | reject(new Error("Username must be at least 3 characters")); | ||
| + | } else if (!formData.email.includes("@")) { | ||
| + | reject(new Error("Invalid email address")); | ||
| + | } else { | ||
| + | resolve(); | ||
| + | } | ||
| + | }); | ||
| + | } | ||
| + | |||
| + | var formData = { | ||
| + | username: "johndoe", | ||
| + | email: "[email protected]" | ||
| + | }; | ||
| + | |||
| + | validateForm(formData) | ||
| + | .then(function() { | ||
| + | submitForm(formData); | ||
| + | }) | ||
| + | .catch(function(error) { | ||
| + | showError(error.message); | ||
| + | }); | ||
| + | --> | ||
| + | </li> | ||
<li>Make a web page with a button (button text: Load image), when we click on that button you have use "promises" to load an image from your server and catch the errors, if there are | <li>Make a web page with a button (button text: Load image), when we click on that button you have use "promises" to load an image from your server and catch the errors, if there are | ||
<!-- function loadImage(url) { | <!-- function loadImage(url) { | ||
Revisió del 12:35, 31 gen 2023
volver a M06 Desarrollo web en entorno cliente
Resources
Exercises
- Create a form with 3 fields at the least
- Make a web page with a button (button text: Load image), when we click on that button you have use "promises" to load an image from your server and catch the errors, if there are
- With the given code, create a web page that call a server with some data (it's doesn't matter what data) and print the data on the page applying some kind of format.
const loadJSON = (file) => { return new Promise((resolve, reject) => { const xhr = new XMLHttpRequest(); xhr.open('GET', file, true); xhr.responseType = 'json'; xhr.onload = () => { if (xhr.status === 200) { resolve(xhr.response); } else { reject(xhr.statusText); } }; xhr.onerror = () => reject(xhr.statusText); xhr.send(); }); };