injecting
v2.9.0
Published
a simple javascript dependency injection module
Downloads
73
Readme
Injecting
A simple javascript dependency inject processor, work great with Promise.
Example
simple injection:
var injecting = require('injecting');
var app = injecting();
app.register('name', 'jack');
app.register('person', function(name) {
this.name = name;
});
app.invoke(function(person) {
console.log(person.name); // jack
});
recursive injection:
var injecting = require('injecting');
var app = injecting();
app.register('place', 'pacific');
app.register('cat', function() {
this.name = "white cat";
});
app.register('person', function(cat) {
this.name = "robot";
this.pet = cat;
});
app.register('story', function(place, person){
return {
place: place,
person: person.name,
pet: person.pet.name
};
});
app.invoke(function(story){
console.log(story);
/* should be
{
place: 'pacific',
person: 'robot',
pet: 'white cat'
};
*/
});
Async Function
var injecting = require('injecting');
var app = injecting();
function sleep(ms) {
return new Promise(function(resolve) {
setTimeout(function () {
resolve('');
}, ms);
});
}
// function that return a promise
app.register('name', function() {
return sleep(1000).then(() =>'jack');
});
// generator as async function and inject `name`
app.register('person', function* (name) {
yield sleep(1000);
return {name: name, age: 10};
});
app
.get('person')
.then(function(person) {
console.log(person); // should be {name: 'jack', age: 10}
});
Anti Minification
The code shows above does not robust enough when our source code is minified. For example:
app.register('person', 'jack');
app.invoke(function(person) {
console.log(person);
});
// will be minified as
app.invoke(function(a) {
console.log(a);
});
// it will lead to app crush in such case since `a` is not registered.
Solution
There are several method to avoid minification problem. Look at the code below:
// invoke a function with predefined injections
app.invoke(['person', 'job', function(p, j) {
console.log(p, j);
});
// register a dep with predefined injections
app.register('person', ['name', 'age', function (n, a) {
return {name: n, age: a};
});
Please refer to the test cases for more examples.
methods
constant(name, value)
register a constant as dependency.
service(name, constructor)
register a service as dependency. notice you have to pass a function for it. injecting
will call the constructor and return the instance the first time you inject. It will return the same instance for later use.
register(name, obj|fn)
register the argument as dependency. automatically register as constant if the second argument is object|string|number, and register as service if the second argument is function.
invoke(fn)
invoke a function and automatically inject for its arguments. Expect to return a promise.
get(name)
get a particular injection in promise form.
License
MIT