https://github.com/angular/angular
Tip revision: 3eda005680efeec37da310c0fee8dff90cae0740 authored by Andrew Kushnir on 14 February 2024, 22:51:37 UTC
release: cut the v17.2.1 release
release: cut the v17.2.1 release
Tip revision: 3eda005
attrs_utils.ts
/**
* @license
* Copyright Google LLC 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 {CharCode} from '../../util/char_code';
import { AttributeMarker } from '../interfaces/attribute_marker';
import {TAttributes} from '../interfaces/node';
import {CssSelector} from '../interfaces/projection';
import {Renderer} from '../interfaces/renderer';
import {RElement} from '../interfaces/renderer_dom';
/**
* Assigns all attribute values to the provided element via the inferred renderer.
*
* This function accepts two forms of attribute entries:
*
* default: (key, value):
* attrs = [key1, value1, key2, value2]
*
* namespaced: (NAMESPACE_MARKER, uri, name, value)
* attrs = [NAMESPACE_MARKER, uri, name, value, NAMESPACE_MARKER, uri, name, value]
*
* The `attrs` array can contain a mix of both the default and namespaced entries.
* The "default" values are set without a marker, but if the function comes across
* a marker value then it will attempt to set a namespaced value. If the marker is
* not of a namespaced value then the function will quit and return the index value
* where it stopped during the iteration of the attrs array.
*
* See [AttributeMarker] to understand what the namespace marker value is.
*
* Note that this instruction does not support assigning style and class values to
* an element. See `elementStart` and `elementHostAttrs` to learn how styling values
* are applied to an element.
* @param renderer The renderer to be used
* @param native The element that the attributes will be assigned to
* @param attrs The attribute array of values that will be assigned to the element
* @returns the index value that was last accessed in the attributes array
*/
export function setUpAttributes(renderer: Renderer, native: RElement, attrs: TAttributes): number {
let i = 0;
while (i < attrs.length) {
const value = attrs[i];
if (typeof value === 'number') {
// only namespaces are supported. Other value types (such as style/class
// entries) are not supported in this function.
if (value !== AttributeMarker.NamespaceURI) {
break;
}
// we just landed on the marker value ... therefore
// we should skip to the next entry
i++;
const namespaceURI = attrs[i++] as string;
const attrName = attrs[i++] as string;
const attrVal = attrs[i++] as string;
ngDevMode && ngDevMode.rendererSetAttribute++;
renderer.setAttribute(native, attrName, attrVal, namespaceURI);
} else {
// attrName is string;
const attrName = value as string;
const attrVal = attrs[++i];
// Standard attributes
ngDevMode && ngDevMode.rendererSetAttribute++;
if (isAnimationProp(attrName)) {
renderer.setProperty(native, attrName, attrVal);
} else {
renderer.setAttribute(native, attrName, attrVal as string);
}
i++;
}
}
// another piece of code may iterate over the same attributes array. Therefore
// it may be helpful to return the exact spot where the attributes array exited
// whether by running into an unsupported marker or if all the static values were
// iterated over.
return i;
}
/**
* Test whether the given value is a marker that indicates that the following
* attribute values in a `TAttributes` array are only the names of attributes,
* and not name-value pairs.
* @param marker The attribute marker to test.
* @returns true if the marker is a "name-only" marker (e.g. `Bindings`, `Template` or `I18n`).
*/
export function isNameOnlyAttributeMarker(marker: string|AttributeMarker|CssSelector) {
return marker === AttributeMarker.Bindings || marker === AttributeMarker.Template ||
marker === AttributeMarker.I18n;
}
export function isAnimationProp(name: string): boolean {
// Perf note: accessing charCodeAt to check for the first character of a string is faster as
// compared to accessing a character at index 0 (ex. name[0]). The main reason for this is that
// charCodeAt doesn't allocate memory to return a substring.
return name.charCodeAt(0) === CharCode.AT_SIGN;
}
/**
* Merges `src` `TAttributes` into `dst` `TAttributes` removing any duplicates in the process.
*
* This merge function keeps the order of attrs same.
*
* @param dst Location of where the merged `TAttributes` should end up.
* @param src `TAttributes` which should be appended to `dst`
*/
export function mergeHostAttrs(dst: TAttributes|null, src: TAttributes|null): TAttributes|null {
if (src === null || src.length === 0) {
// do nothing
} else if (dst === null || dst.length === 0) {
// We have source, but dst is empty, just make a copy.
dst = src.slice();
} else {
let srcMarker: AttributeMarker = AttributeMarker.ImplicitAttributes;
for (let i = 0; i < src.length; i++) {
const item = src[i];
if (typeof item === 'number') {
srcMarker = item;
} else {
if (srcMarker === AttributeMarker.NamespaceURI) {
// Case where we need to consume `key1`, `key2`, `value` items.
} else if (
srcMarker === AttributeMarker.ImplicitAttributes ||
srcMarker === AttributeMarker.Styles) {
// Case where we have to consume `key1` and `value` only.
mergeHostAttribute(dst, srcMarker, item as string, null, src[++i] as string);
} else {
// Case where we have to consume `key1` only.
mergeHostAttribute(dst, srcMarker, item as string, null, null);
}
}
}
}
return dst;
}
/**
* Append `key`/`value` to existing `TAttributes` taking region marker and duplicates into account.
*
* @param dst `TAttributes` to append to.
* @param marker Region where the `key`/`value` should be added.
* @param key1 Key to add to `TAttributes`
* @param key2 Key to add to `TAttributes` (in case of `AttributeMarker.NamespaceURI`)
* @param value Value to add or to overwrite to `TAttributes` Only used if `marker` is not Class.
*/
export function mergeHostAttribute(
dst: TAttributes, marker: AttributeMarker, key1: string, key2: string|null,
value: string|null): void {
let i = 0;
// Assume that new markers will be inserted at the end.
let markerInsertPosition = dst.length;
// scan until correct type.
if (marker === AttributeMarker.ImplicitAttributes) {
markerInsertPosition = -1;
} else {
while (i < dst.length) {
const dstValue = dst[i++];
if (typeof dstValue === 'number') {
if (dstValue === marker) {
markerInsertPosition = -1;
break;
} else if (dstValue > marker) {
// We need to save this as we want the markers to be inserted in specific order.
markerInsertPosition = i - 1;
break;
}
}
}
}
// search until you find place of insertion
while (i < dst.length) {
const item = dst[i];
if (typeof item === 'number') {
// since `i` started as the index after the marker, we did not find it if we are at the next
// marker
break;
} else if (item === key1) {
// We already have same token
if (key2 === null) {
if (value !== null) {
dst[i + 1] = value;
}
return;
} else if (key2 === dst[i + 1]) {
dst[i + 2] = value!;
return;
}
}
// Increment counter.
i++;
if (key2 !== null) i++;
if (value !== null) i++;
}
// insert at location.
if (markerInsertPosition !== -1) {
dst.splice(markerInsertPosition, 0, marker);
i = markerInsertPosition + 1;
}
dst.splice(i++, 0, key1);
if (key2 !== null) {
dst.splice(i++, 0, key2);
}
if (value !== null) {
dst.splice(i++, 0, value);
}
}