angular-cn/modules/@angular/compiler/src/i18n/expander.ts

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2016-05-31 18:22:59 -04:00
import {BaseException} from '../facade/exceptions';
import {HtmlAst, HtmlAstVisitor, HtmlAttrAst, HtmlCommentAst, HtmlElementAst, HtmlExpansionAst, HtmlExpansionCaseAst, HtmlTextAst, htmlVisitAll} from '../html_ast';
/**
* Expands special forms into elements.
*
* For example,
*
* ```
* { messages.length, plural,
* =0 {zero}
* =1 {one}
* =other {more than one}
* }
* ```
*
* will be expanded into
*
* ```
* <ul [ngPlural]="messages.length">
* <template [ngPluralCase]="0"><li i18n="plural_0">zero</li></template>
* <template [ngPluralCase]="1"><li i18n="plural_1">one</li></template>
* <template [ngPluralCase]="other"><li i18n="plural_other">more than one</li></template>
* </ul>
* ```
*/
export function expandNodes(nodes: HtmlAst[]): ExpansionResult {
let e = new _Expander();
let n = htmlVisitAll(e, nodes);
return new ExpansionResult(n, e.expanded);
}
export class ExpansionResult {
constructor(public nodes: HtmlAst[], public expanded: boolean) {}
}
class _Expander implements HtmlAstVisitor {
expanded: boolean = false;
constructor() {}
visitElement(ast: HtmlElementAst, context: any): any {
return new HtmlElementAst(
ast.name, ast.attrs, htmlVisitAll(this, ast.children), ast.sourceSpan, ast.startSourceSpan,
ast.endSourceSpan);
}
visitAttr(ast: HtmlAttrAst, context: any): any { return ast; }
visitText(ast: HtmlTextAst, context: any): any { return ast; }
visitComment(ast: HtmlCommentAst, context: any): any { return ast; }
visitExpansion(ast: HtmlExpansionAst, context: any): any {
this.expanded = true;
return ast.type == 'plural' ? _expandPluralForm(ast) : _expandDefaultForm(ast);
}
visitExpansionCase(ast: HtmlExpansionCaseAst, context: any): any {
throw new BaseException('Should not be reached');
}
}
function _expandPluralForm(ast: HtmlExpansionAst): HtmlElementAst {
let children = ast.cases.map(c => {
let expansionResult = expandNodes(c.expression);
let i18nAttrs = expansionResult.expanded ?
[] :
[new HtmlAttrAst('i18n', `${ast.type}_${c.value}`, c.valueSourceSpan)];
return new HtmlElementAst(
`template`,
[
new HtmlAttrAst('ngPluralCase', c.value, c.valueSourceSpan),
],
[new HtmlElementAst(
`li`, i18nAttrs, expansionResult.nodes, c.sourceSpan, c.sourceSpan, c.sourceSpan)],
c.sourceSpan, c.sourceSpan, c.sourceSpan);
});
let switchAttr = new HtmlAttrAst('[ngPlural]', ast.switchValue, ast.switchValueSourceSpan);
return new HtmlElementAst(
'ul', [switchAttr], children, ast.sourceSpan, ast.sourceSpan, ast.sourceSpan);
}
function _expandDefaultForm(ast: HtmlExpansionAst): HtmlElementAst {
let children = ast.cases.map(c => {
let expansionResult = expandNodes(c.expression);
let i18nAttrs = expansionResult.expanded ?
[] :
[new HtmlAttrAst('i18n', `${ast.type}_${c.value}`, c.valueSourceSpan)];
return new HtmlElementAst(
`template`,
[
new HtmlAttrAst('ngSwitchWhen', c.value, c.valueSourceSpan),
],
[new HtmlElementAst(
`li`, i18nAttrs, expansionResult.nodes, c.sourceSpan, c.sourceSpan, c.sourceSpan)],
c.sourceSpan, c.sourceSpan, c.sourceSpan);
});
let switchAttr = new HtmlAttrAst('[ngSwitch]', ast.switchValue, ast.switchValueSourceSpan);
return new HtmlElementAst(
'ul', [switchAttr], children, ast.sourceSpan, ast.sourceSpan, ast.sourceSpan);
}