Dojo AMD: Can't call a function inside a require

问题

I am really a newbie to dojo but as i started developing a new application with dojo version 1.7.2 i also wanted to use the new AMD syntax for functions. Unfortunately i don't seem to get it. :-(

What annoys me most is that i can't simply call any function which is inside of a "require"-block. For example i have a page which on opening creates a dynamic table with several widgets in each row. Then i have a button which adds one empty row each time pressed.

Without AMD syntax it would be easy:
- put all my "dojo.require()" in the HEAD
- and then create a bunch of my own functions for creating the table and widgets
- the add row function could easily access any global-variables my previous function filled

But with AMD its like this:

Initial function creates the table and widgets:

function fillReportTable(repId) {
require(["dojo/dom-construct", "dojo/dom-attr", "dijit/form/FilteringSelect",
"dojo/data/ItemFileReadStore", "dijit/form/ComboBox", "dijit/form/DateTextBox", "dijit/form/Select", "dojo/store/Memory"],
     function (domConstruct, domAttr, FilteringSelect, ItemFileReadStore, ComboBox, DateTextBox, Select, Memory) {
   // a lot of code to create the table, consisting of SEVERAL functions 
   function createNewRow(tbl) { ...} 
   function function1 () {... } 
   function function2 () {... } 
   function function3 () {... } 
}

Now the "Add Empty Row" button calls its own function "addEmptyRow".
But in this function I have to:
- do an other require for each dojo-module again
- I CAN'T use any of the functions which are "inside" of the "fillReportTable"-function. For example the "createNewRow"-function

 function addEmptyRow() {
require(["dojo/dom-construct", "dojo/dom-attr", "dijit/form/FilteringSelect",
"dojo/data/ItemFileReadStore", "dijit/form/ComboBox", "dijit/form/DateTextBox", "dijit/form/Select", "dojo/store/Memory"],
     function (domConstruct, domAttr, FilteringSelect, ItemFileReadStore, ComboBox, DateTextBox, Select, Memory) {
// a lot of code to create the table, consisting of SEVERAL functions
}

This all seems to be so much complicated with AMD.
Or am i missing something obvious here ?
With AMD if you separate your code into a lot of small functions, do you do the "require" inside EACH function all over again ? Or do you put all the functions inside one "require" with the full list ?
If you do it the second way, how can you call these functions from widget events?

回答1:

The easiest way would be to define your own module. Take a look at this tutorial first:

http://dojotoolkit.org/documentation/tutorials/1.7/modules/

Now define your own module, e.g. "./js/mymodules/mymodule.js" (relative to HTML page):

define([
    "dojo/dom-construct",
    "dojo/dom-attr",
    "dijit/form/FilteringSelect",
    "dojo/data/ItemFileReadStore",
    "dijit/form/ComboBox",
    "dijit/form/DateTextBox",
    "dijit/form/Select",
    "dojo/store/Memory"
], function (domConstruct, domAttr, FilteringSelect, ItemFileReadStore, ComboBox, DateTextBox, Select, Memory) {

    function fillReportTable(repId) {
       // a lot of code to create the table, consisting of SEVERAL functions 
       function createNewRow(tbl) { ...} 
       function function1 () {... } 
       function function2 () {... } 
       function function3 () {... } 
    }

    function addEmptyRow() {
       // a lot of code to create the table, consisting of SEVERAL functions
    }

    // Return an object that exposes two functions
    return {
        fillReportTable: fillReportTable,
        addEmptyRow: addEmptyRow
    }

});

And use your module like this:

<html>

<head>

<script>
var dojoConfig = {
    baseUrl: "./js/",
    packages: [
        { name: "dojo", location: "lib/dojo" },
        { name: "dijit", location: "lib/dijit" },
        { name: "dojox", location: "lib/dojox" }
    ]
};
</script>

<script data-dojo-config="async: true" src="js/lib/dojo/dojo.js"></script>

</head>

...

<script>
require([
    "mymodules/mymodule"
], function (mymodule) {
    mymodule.fillReportTable(...);
    mymodule.addEmptyRow(...);
});
</script>

回答2:

Try this:

require([...], function() {
    var myFunctions = dojo.getObject('myFunctions', true);
    myFunctions.createNewRow = function(...) {
        ...
    };
});

You can now call your functions from anywhere by using

myFunctions.createNewRow();

If you don't want 'myFunctions', you could do

require([...], function() {
    var createNewRow = function(...) {};

    dojo.setObject('createNewRow', createNewRow);
});

回答3:

Paul Grime gave you a good example, so I'm just sharing some thoughts.

You don't define all the modules in each function, that's a huge waste of space. Although, even if you try to load a module multiple times, Dojo will only load it once anyway.

This is a simplified module from my latest project, with quite meaningless functionality:

//app module in 'my' folder

define(
[
    'app/elements',
    'dojo/query',
    'dojo/on',
    'dojo/fx',
    'dojo/_base/fx',
    'dojo/dom-construct',
    'dojo/_base/event'

    //and so on.....
], 

function(elements, q, on, fx, baseFx, constr, event)
{   
    return {

        init : function()
        {
            var node = q(elements.loading);
            this.removeNode(node);

            this.addEvents();
        },

        removeNode : function(node)
        {
            node.remove();
        },

        addEvents : function()
        {
            $(elements.buttons).on('click', function(e)
            {
                alert(q(e).attr('id') + ' was clicked!');
            });
        }   
    }
}

Then I get the module by using

define(
[
    'my/app',
], 

function (app) 
{
    app.init();
}

来源：https://stackoverflow.com/questions/9626821/dojo-amd-cant-call-a-function-inside-a-require

标签

dojo

javascript-framework

amd