pipeNamingRule.ts

import * as Lint from 'tslint/lib/lint';
import * as ts from 'typescript';
import {sprintf} from 'sprintf-js';
import SyntaxKind = require('./util/syntaxKind');
import {Ng2Walker} from './angular/ng2Walker';
import {SelectorValidator} from './util/selectorValidator';

export class Rule extends Lint.Rules.AbstractRule {
  static  FAILURE_WITHOUT_PREFIX: string = 'The name of the Pipe decorator of class %s should' +
    ' be named camelCase, however its value is "%s".';

  static  FAILURE_WITH_PREFIX: string = 'The name of the Pipe decorator of class %s should' +
    ' be named camelCase with prefix %s, however its value is "%s".';

  public prefix: string;
  public hasPrefix: boolean;
  private prefixChecker: Function;
  private validator: Function;

  constructor(ruleName:string, value:any, disabledIntervals:Lint.IDisabledInterval[]) {
    super(ruleName, value, disabledIntervals);
    if (value[1] === 'camelCase') {
      this.validator = SelectorValidator.camelCase;
    }
    if (value.length>2) {
      this.hasPrefix = true;
      let prefixExpression:string = (value.slice(2)||[]).join('|');
      this.prefix =(value.slice(2)||[]).join(',');
      this.prefixChecker = SelectorValidator.multiPrefix(prefixExpression);
    }
  }

  public apply(sourceFile:ts.SourceFile):Lint.RuleFailure[] {
    return this.applyWithWalker(
      new ClassMetadataWalker(sourceFile, this));
  }

  public validateName(name:string):boolean {
    return this.validator(name);
  }

  public validatePrefix(prefix:string):boolean {
    return this.prefixChecker(prefix);
  }
}

export class ClassMetadataWalker extends Ng2Walker {

  constructor(sourceFile:ts.SourceFile, private rule:Rule) {
    super(sourceFile, rule.getOptions());
  }

  visitNg2Pipe(controller: ts.ClassDeclaration, decorator: ts.Decorator) {
    let className = controller.name.text;
    this.validateProperties(className, decorator);
  }

  private validateProperties(className:string, pipe:any) {
    let argument = this.extractArgument(pipe);
    if (argument.kind === SyntaxKind.current().ObjectLiteralExpression) {
      argument.properties.filter(n=>n.name.text === 'name')
        .forEach(this.validateProperty.bind(this, className))
    }
  }

  private extractArgument(pipe:any) {
    let baseExpr = <any>pipe.expression || {};
    let args = baseExpr.arguments || [];
    return args[0];
  }

  private validateProperty(className:string, property:any) {
    let propName:string = property.initializer.text;
    let isValidName:boolean = this.rule.validateName(propName);
    let isValidPrefix:boolean = (this.rule.hasPrefix?this.rule.validatePrefix(propName):true);
    if (!isValidName || !isValidPrefix) {
      this.addFailure(
        this.createFailure(
          property.getStart(),
          property.getWidth(),
          sprintf.apply(this, this.createFailureArray(className, propName))));
    }
  }

  private createFailureArray(className:string, pipeName:string):Array<string> {
    if (this.rule.hasPrefix) {
      return [Rule.FAILURE_WITH_PREFIX, className, this.rule.prefix, pipeName];
    }
    return [Rule.FAILURE_WITHOUT_PREFIX, className, pipeName];
  }
}