Table of contents
Quick and brief knowledge points
Syntax: seajs.use(id, callback?)
Introduction to seaJS
What is seaJS?
Similar to requireJS, seaJS is also a JS framework written in JavaScript. Its main function is to load JavaScript and other files according to different dependencies. It can be simply understood as a JS file loader, which is very suitable for browsers . Use, it can ensure that the current JS file is loaded after the dependent JS file is loaded. This can ensure the sequential loading order of each JS file in a project that uses a large number of JS files , ensuring that a certain file is avoided for some reason. Slow loading causes other fast-loading files to rely on some of its functions, and a function or variable cannot be found. This is very useful, and it is also the main value of seaJS (comply with CMD); but it is different from requireJS (comply with AMD specifications) differ.
Quick and brief knowledge points
1. seajs.config({...}); //Used to configure Sea.js.
2. seajs.use(['a','b'], function(a,b){...}); //Used to load one or more modules in the page.
3. define(function(require, exports, module){...}); //Used to define modules. Sea.js respects one module and one file, and follows a unified writing method:
4. require(function(require){var a = require("xModule"); ... }); //require is used to obtain the interface of the specified module.
5. require.async, //Used to asynchronously load one or more modules inside the module. For example:
define(function(require){
require.async(['aModule','bModule'],function(a,b){ // 异步加载多个模块，在加载完成时，执行回调
a.func();
b.func();
})
});6. exports, //Used to provide external interfaces inside the module. For example:
define(function(require, exports){
exports.varName01 = 'varValue'; // 对外提供 varName01 属性
exports.funName01 = function(p1,p2){ // 对外提供 funName01 方法
....
}
});7. module.exports, similar to exports, is used to provide external interfaces inside the module. For example:
define(function(require, exports, module) {
module.exports = { // 对外提供接口
name: 'a',
doSomething: function() {...};
};
});Use of seajs
use
seajs.use is used to load modules in the page. Through the use method, any module can be loaded in the page.
<script src="path/to/sea.js"></script>
<script>
seajs.use('./main');
</script>Syntax: seajs.use(id, callback?)
// Load the module main, and when the loading is complete, execute the specified callback
seajs.use('./main', function(main) {
main.init();
});The use method can also load multiple modules at once:
// Load module a and module b concurrently, and execute the specified callback when both are loaded
seajs.use(['./a', './b'], function(a, b) {
a.init();
b.init();
});The callback parameter is optional. When only one module is loaded and no callback is needed, it can be simplified with the data-main attribute:
<script src=”path/to/sea.js” data-main=”./main”></script>Equivalent to
<script src="path/to/sea.js"></script>
<script>
seajs.use('./main');
</script>