9ca2b4c967
Most important for StyleGuide which lost example css class in migration. Also hides copy for “avoid” files.
52 lines
1.8 KiB
TypeScript
52 lines
1.8 KiB
TypeScript
// Utilities for processing HTML element attributes
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import { ElementRef } from '@angular/core';
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interface StringMap { [index: string]: string; }
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/**
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* Get attribute map from element or ElementRef `attributes`.
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* Attribute map keys are forced lowercase for case-insensitive lookup.
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* @param el The source of the attributes
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*/
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export function getAttrs(el: HTMLElement | ElementRef): StringMap {
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const attrs: NamedNodeMap = el instanceof ElementRef ? el.nativeElement.attributes : el.attributes;
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const attrMap = {};
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Object.keys(attrs).forEach(key =>
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attrMap[(attrs[key] as Attr).name.toLowerCase()] = (attrs[key] as Attr).value);
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return attrMap;
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}
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/**
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* Return the attribute that matches `attr`.
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* @param attr Name of the attribute or a string of candidate attribute names
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*/
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export function getAttrValue(attrs: StringMap, attr: string | string[] = ''): string {
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return attrs[typeof attr === 'string' ?
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attr.toLowerCase() :
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attr.find(a => attrs[a.toLowerCase()] !== undefined)
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];
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}
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/**
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* Return the boolean state of an attribute value (if supplied)
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* @param attrValue The string value of some attribute (or undefined if attribute not present)
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* @param def Default boolean value when attribute is undefined.
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*/
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export function boolFromValue(attrValue: string, def: boolean = false) {
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// tslint:disable-next-line:triple-equals
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return attrValue == undefined ? def : attrValue.trim() !== 'false';
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}
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/**
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* Return the boolean state of attribute from an element
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* @param el The source of the attributes
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* @param atty Name of the attribute or a string of candidate attribute names
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* @param def Default boolean value when attribute is undefined.
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*/
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export function getBoolFromAttribute(
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el: HTMLElement | ElementRef,
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attr: string | string[],
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def: boolean = false): boolean {
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return boolFromValue(getAttrValue(getAttrs(el), attr), def);
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}
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