2.1.0 • Published 3 years ago
simpledi-node v2.1.0
SimpleDi
This is a fork and complete rewrite of SimpleDi, a very simple dependency injector.
Intended for Node 10+ environments.
Features
- Simple API
- No dependencies
- Fully tested
- Helps you find unresolved dependencies with
getResolvedDependencyCount
Installation
npm install simpledi-nodeAPI
Create a SimpleDi instance
const SimpleDi = require('simpledi-node');
const di = new SimpleDi(); Add dependency with factory function
di.registerWithFactory(name, factoryFn, dependencies, overwrite)
di.registerWithFactoryOnce(name, factoryFn, dependencies, overwrite)
| Parameter | Type | Description |
|---|---|---|
| name | string | The name of the dependency |
| factoryFn | function | A function that gets called when di.get(name) is called |
| dependencies | string[] | optional array of dependency names. The dependencies will be resolved and passed to the factoryFn when di.get(name) is called. |
| overwrite | boolean | optional This allows to explicitly overwrite dependencies |
Add dependency with class constructor
di.registerWithNew(name, clazz, dependencies, overwrite)
di.registerWithNewOnce(name, clazz, dependencies, overwrite)
| Parameter | Type | Description |
|---|---|---|
| name | string | The name of the dependency |
| clazz | function | A class or constructor function that gets instantiated when di.get(name) is called |
| dependencies | string[] | optional array of dependency names. The dependencies will be resolved and passed to the constructor when di.get(name) is called. |
| overwrite | boolean | optional This allows to explicitly overwrite dependencies |
Example
const SimpleDi = require('simpledi-node');
const di = new SimpleDi();
function Engine(config) {
this.hp = config.hp;
this.maxSpeed = config.maxSpeed;
}
function Car(engine) {
this.text = 'This car has ' + engine.hp + 'hp!';
}
di.registerWithNew('Engine', Engine, ['engineConfig']);
di.registerConstant('engineConfig', {
hp: 120,
maxSpeed: 200
});
di.registerWithNewOnce('Car', Car, ['Engine']);
let car = di.get('Car');
console.log(car.text); // This car has 120hp!Add constant dependency
di.registerConstant(name, value, overwrite)
| Parameter | Type | Description |
|---|---|---|
| name | string | The name of the dependency |
| value | mixed | A fix value to be returned whenever di.get(name) is called |
| overwrite | boolean | optional This allows to explicitly overwrite dependencies |
di.registerContants(keyValueMap, keyPrefix, overwrite)
| Parameter | Type | Description |
|---|---|---|
| keyValueMap | Map<string,*> or Object | An map or pojo whose (own) keys will be used to register the respective value as a constant |
| prefix | string | optional prefix to precede the registered keys |
| overwrite | boolean | optional This allows to explicitly overwrite dependencies |
Example:
const CC = {foo: 1, bar: 2};
di.registerConstants(CC);
di.get('foo'); // returns 1
di.registerConstants(CC, 'tmp.');
di.get('tmp.bar'); // returns 2Get a dependency
di.get(name[, arg1[, arg2[, ...]]])
Returns a previously registered dependency and resolves all dependencies.
Throws an Error if the dependency is not registered.
| Name | Type | Description |
|---|---|---|
| name | string | The name of the dependency |
| arg1, arg2, ... | mixed | optional arguments that will be passed to the dependency's factory function or constructor additionally to its dependencies |
Example:
const fn = function() { return [...arguments] };
di.registerWithFactory('foo', fn, ['BAR']);
di.registerConstant('BAR', 111);
di.get('foo', 444, 555); // returns [111, 444, 555]NOTE: For dependencies registered via registerWithNewOnce() or registerWithFactoryOnce(),
additional get-arguments (arg1, arg2, ...) are allowed only in the first invocation of di.get().
An error is thrown otherwise.
You can suppress this error by calling di.setIgnoreArgsPassedToFinalValue(true).
Example for circular dependency (throws error):
di.registerWithNew('A', class{}, ['B']);
di.registerWithNew('B', class{}, ['C']);
di.registerWithNew('C', class{}, ['A']);
di.get('A'); // throws "Circular Dependency detected: A => B => C => A"Inspecting usages of dependencies
di.getResolvedDependencyCount(): Map<string, number>
Returns a Map of dependency names onto the number the dependency got resolved in total,
including both direct di.get() calls and transitive resolving.
// Example
console.warn(...di.getResolvedDependencyCount()); // [ 'foo', 3 ] [ 'bar', 1 ]