feat(forms): add easy way to switch between forms modules (#9202)

modules/@angular/forms/src/form_builder.ts

@@ -0,0 +1,115 @@
+import {Injectable} from '@angular/core';
+
+import {AsyncValidatorFn, ValidatorFn} from './directives/validators';
+import {StringMapWrapper} from './facade/collection';
+import {isArray, isPresent} from './facade/lang';
+import * as modelModule from './model';
+
+
+
+/**
+ * Creates a form object from a user-specified configuration.
+ *
+ * ```typescript
+ * @Component({
+ *   selector: 'my-app',
+ *   template: `
+ *     <form [formGroup]="loginForm">
+ *       <p>Login <input formControlName="login"></p>
+ *       <div formGroupName="passwordRetry">
+ *         <p>Password <input type="password" formControlName="password"></p>
+ *         <p>Confirm password <input type="password" formControlName="passwordConfirmation"></p>
+ *       </div>
+ *     </form>
+ *     <h3>Form value:</h3>
+ *     <pre>{{value}}</pre>
+ *   `,
+ *   directives: [REACTIVE_FORM_DIRECTIVES]
+ * })
+ * export class App {
+ *   loginForm: FormGroup;
+ *
+ *   constructor(builder: FormBuilder) {
+ *     this.loginForm = builder.group({
+ *       login: ["", Validators.required],
+ *       passwordRetry: builder.group({
+ *         password: ["", Validators.required],
+ *         passwordConfirmation: ["", Validators.required, asyncValidator]
+ *       })
+ *     });
+ *   }
+ *
+ *   get value(): string {
+ *     return JSON.stringify(this.loginForm.value, null, 2);
+ *   }
+ * }
+ * ```
+ *
+ * @experimental
+ */
+@Injectable()
+export class FormBuilder {
+  /**
+   * Construct a new {@link FormGroup} with the given map of configuration.
+   * Valid keys for the `extra` parameter map are `optionals` and `validator`.
+   *
+   * See the {@link FormGroup} constructor for more details.
+   */
+  group(controlsConfig: {[key: string]: any}, extra: {[key: string]: any} = null):
+      modelModule.FormGroup {
+    var controls = this._reduceControls(controlsConfig);
+    var optionals = <{[key: string]: boolean}>(
+        isPresent(extra) ? StringMapWrapper.get(extra, 'optionals') : null);
+    var validator: ValidatorFn = isPresent(extra) ? StringMapWrapper.get(extra, 'validator') : null;
+    var asyncValidator: AsyncValidatorFn =
+        isPresent(extra) ? StringMapWrapper.get(extra, 'asyncValidator') : null;
+    return new modelModule.FormGroup(controls, optionals, validator, asyncValidator);
+  }
+  /**
+   * Construct a new {@link FormControl} with the given `value`,`validator`, and `asyncValidator`.
+   */
+  control(
+      value: Object, validator: ValidatorFn|ValidatorFn[] = null,
+      asyncValidator: AsyncValidatorFn|AsyncValidatorFn[] = null): modelModule.FormControl {
+    return new modelModule.FormControl(value, validator, asyncValidator);
+  }
+
+  /**
+   * Construct an array of {@link FormControl}s from the given `controlsConfig` array of
+   * configuration, with the given optional `validator` and `asyncValidator`.
+   */
+  array(
+      controlsConfig: any[], validator: ValidatorFn = null,
+      asyncValidator: AsyncValidatorFn = null): modelModule.FormArray {
+    var controls = controlsConfig.map(c => this._createControl(c));
+    return new modelModule.FormArray(controls, validator, asyncValidator);
+  }
+
+  /** @internal */
+  _reduceControls(controlsConfig: {[k: string]: any}):
+      {[key: string]: modelModule.AbstractControl} {
+    var controls: {[key: string]: modelModule.AbstractControl} = {};
+    StringMapWrapper.forEach(controlsConfig, (controlConfig: any, controlName: string) => {
+      controls[controlName] = this._createControl(controlConfig);
+    });
+    return controls;
+  }
+
+  /** @internal */
+  _createControl(controlConfig: any): modelModule.AbstractControl {
+    if (controlConfig instanceof modelModule.FormControl ||
+        controlConfig instanceof modelModule.FormGroup ||
+        controlConfig instanceof modelModule.FormArray) {
+      return controlConfig;
+
+    } else if (isArray(controlConfig)) {
+      var value = controlConfig[0];
+      var validator: ValidatorFn = controlConfig.length > 1 ? controlConfig[1] : null;
+      var asyncValidator: AsyncValidatorFn = controlConfig.length > 2 ? controlConfig[2] : null;
+      return this.control(value, validator, asyncValidator);
+
+    } else {
+      return this.control(controlConfig);
+    }
+  }
+}