2018-09-21 14:51:24 -07:00

124 lines
3.8 KiB
TypeScript

/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {devModeEqual} from '../change_detection/change_detection_util';
import {assertDefined, assertLessThan} from './assert';
import {readElementValue, readPatchedLViewData} from './context_discovery';
import {LContainerNode, LElementContainerNode, LElementNode, TNode, TNodeFlags} from './interfaces/node';
import {CONTEXT, FLAGS, HEADER_OFFSET, LViewData, LViewFlags, PARENT, RootContext, TData} from './interfaces/view';
/**
* Returns whether the values are different from a change detection stand point.
*
* Constraints are relaxed in checkNoChanges mode. See `devModeEqual` for details.
*/
export function isDifferent(a: any, b: any, checkNoChangesMode: boolean): boolean {
if (ngDevMode && checkNoChangesMode) {
return !devModeEqual(a, b);
}
// NaN is the only value that is not equal to itself so the first
// test checks if both a and b are not NaN
return !(a !== a && b !== b) && a !== b;
}
export function stringify(value: any): string {
if (typeof value == 'function') return value.name || value;
if (typeof value == 'string') return value;
if (value == null) return '';
return '' + value;
}
/**
* Function that throws a "not implemented" error so it's clear certain
* behaviors/methods aren't yet ready.
*
* @returns Not implemented error
*/
export function notImplemented(): Error {
return new Error('NotImplemented');
}
/**
* Flattens an array in non-recursive way. Input arrays are not modified.
*/
export function flatten(list: any[]): any[] {
const result: any[] = [];
let i = 0;
while (i < list.length) {
const item = list[i];
if (Array.isArray(item)) {
if (item.length > 0) {
list = item.concat(list.slice(i + 1));
i = 0;
} else {
i++;
}
} else {
result.push(item);
i++;
}
}
return result;
}
/** Retrieves a value from any `LViewData` or `TData`. */
export function loadInternal<T>(index: number, arr: LViewData | TData): T {
ngDevMode && assertDataInRangeInternal(index + HEADER_OFFSET, arr);
return arr[index + HEADER_OFFSET];
}
export function assertDataInRangeInternal(index: number, arr: any[]) {
assertLessThan(index, arr ? arr.length : 0, 'index expected to be a valid data index');
}
/** Retrieves an element value from the provided `viewData`.
*
* Elements that are read may be wrapped in a style context,
* therefore reading the value may involve unwrapping that.
*/
export function loadElementInternal(index: number, arr: LViewData): LElementNode {
const value = loadInternal<LElementNode>(index, arr);
return readElementValue(value);
}
export function getLNode(tNode: TNode, hostView: LViewData): LElementNode|LContainerNode|
LElementContainerNode {
return readElementValue(hostView[tNode.index]);
}
export function isContentQueryHost(tNode: TNode): boolean {
return (tNode.flags & TNodeFlags.hasContentQuery) !== 0;
}
export function isComponent(tNode: TNode): boolean {
return (tNode.flags & TNodeFlags.isComponent) === TNodeFlags.isComponent;
}
/**
* Retrieve the root view from any component by walking the parent `LViewData` until
* reaching the root `LViewData`.
*
* @param component any component
*/
export function getRootView(target: LViewData | {}): LViewData {
ngDevMode && assertDefined(target, 'component');
let lViewData = Array.isArray(target) ? (target as LViewData) : readPatchedLViewData(target) !;
while (lViewData && !(lViewData[FLAGS] & LViewFlags.IsRoot)) {
lViewData = lViewData[PARENT] !;
}
return lViewData;
}
export function getRootContext(viewOrComponent: LViewData | {}): RootContext {
return getRootView(viewOrComponent)[CONTEXT] as RootContext;
}