随着前端框架的诞生，也会随之呈现一些组件库，不便日常业务开发。明天就聊聊 angular4 组件库开发流程。

下图是 button 组件的根底文件。

nk-button.component.ts 为该组件的外围文件，看看代码：

import {Component, Renderer2, ElementRef, AfterContentInit, ViewEncapsulation, Input} from '@angular/core';
 
@Component({selector: '[nk-button]',
  templateUrl: './nk-button.component.html',
  encapsulation: ViewEncapsulation.None,
  styleUrls: ['./nk-button.component.scss']
})
export class NkButtonComponent implements AfterContentInit {
  _el: HTMLElement;
  _prefixCls = 'ky-btn';
  _type: string;
  _size: string;
  _shape: string;
  _classList: Array<string> = [];
 
  @Input()
  get nkType() {return this._type;}
 
  set nkType(value) {
    this._type = value;
    this._setClass();}
 
  @Input()
  get nkSize() {return this._size;}
 
  set nkSize(value: string) {
    this._size = value;
    this._setClass();}
 
  @Input()
  get nkShape() {return this._shape;}
 
  set nkShape(value: string) {
    this._shape = value;
    this._setClass();}
 
  constructor(private _elementRef: ElementRef, private _renderer: Renderer2) {
    this._el = this._elementRef.nativeElement;
    this._renderer.addClass(this._el, this._prefixCls);
  }
 
  ngAfterContentInit() {}
 
  /**
   * 设置 class 属性
   */
  _setClass(): void {
    this._classList = [this.nkType && `${this._prefixCls}-${this.nkType}`,
      this.nkSize && `${this._prefixCls}-${this.nkSize}`,
      this.nkShape && `${this._prefixCls}-${this.nkShape}`
    ].filter(item => {return item;});
    this._classList.forEach(_className => {this._renderer.addClass(this._el, _className);
    });
  }
}

针对外围概念 ElementRef、Renderer2、ViewEncapsulation 做简要阐明：

ElementRef

在应用层间接操作 DOM，就会造成应用层与渲染层之间强耦合，通过 ElementRef 咱们就能够封装不同平台下视图层中的 native 元素 (在浏览器环境中，native 元素通常是指 DOM 元素)，最初借助于 Angular 提供的弱小的依赖注入个性，咱们就能够轻松地拜访到 native 元素。

参考链接

Renderer2

渲染器是 Angular 为咱们提供的一种内置服务，用于执行 UI 渲染操作。在浏览器中，渲染是将模型映射到视图的过程。模型的值能够是 JavaScript 中的原始数据类型、对象、数组或其它的数据对象。然而视图能够是页面中的段落、表单、按钮等其余元素，这些页面元素外部应用 DOM 来示意。

参考链接

ViewEncapsulation

ViewEncapsulation 容许设置三个可选的值：

• ViewEncapsulation.Emulated – 无 Shadow DOM，然而通过 Angular 提供的款式包装机制来封装组件，使得组件的款式不受内部影响。这是 Angular 的默认设置。
• ViewEncapsulation.Native – 应用原生的 Shadow DOM 个性
• ViewEncapsulation.None – 无 Shadow DOM，并且也无款式包装

参考链接

button 组件创立思路：

• 针对 button 咱们只需批改其款式，因而在这里创立属性指令
• 提供属性接口
• 依据其传入的属性值动静渲染 DOM

至此，最简略的 button 就开发完结。

模块打包流程

合并 html、css 到 component 文件

let fs = require("fs");
let pathUtil = require("path");
let sass = require("node-sass");
let filePath = pathUtil.join(__dirname, "src", "temp_components");
 
let fileArray = [];
 
function fildFile(path) {if (fs.statSync(path).isFile()) {if (/\.component.ts/.test(path)) {fileArray[0] = path;
    }
    if (/\.html$/.test(path)) {fileArray[1] = readFile(path);
    }
    if (/\.component.scss$/.test(path)) {fileArray[2] = path;
    }
  } else if (fs.statSync(path).isDirectory()) {let paths = fs.readdirSync(path);
 
    if (fileArray.length === 3) {writeFile(fileArray);
      fileArray = [];}
    paths.forEach((p) => {fildFile(pathUtil.join(path, p));
    });
  }
}
 
function readFile(file) {return fs.readFileSync(file);
}
 
function writeFile(fileArray) {let file = fileArray[0];
  let content = fileArray[1];
  let scssPath = fileArray[2];
  mergeContent(file, content, scssPath).then((result) => {if (!result) return;
    fs.writeFile(file, result, function (err) {if (err) console.error(err);
      console.log("file merge success!");
    });
  });
}
 
/**
 * 转换 scss
 * @param path
 * @returns {Promise}
 */
function processScss(path) {return new Promise((resolve, reject) => {
    sass.render(
      {file: path,},
      (err, result) => {if (!err) {resolve(result.css.toString());
        } else {reject(err);
        }
      }
    );
  });
}
 
function mergeContent(file, content, scssPath) {let componentContent = readFile(file);
  let htmlRegex = /(templateUrl *:\s*[\"|\'])(.*[\"|\']\,?)/g;
  let scssRegex = /(styleUrls *:\s*)(\[.*\]\,?)/g;
 
  let newContent = "";
  if (htmlRegex.test(componentContent) && scssRegex.test(componentContent)) {let contentArray = componentContent.toString().split(htmlRegex);
    contentArray[1] = "template:`";
    contentArray[2] = content + "`,";
    contentArray.forEach((con) => {newContent += con;});
    contentArray = newContent.toString().split(scssRegex);
 
    return new Promise((resolve, reject) => {processScss(scssPath).then((result) => {
          newContent = "";
          contentArray[1] = "styles:[`";
          contentArray[2] = result + "`],";
          contentArray.forEach((con) => {newContent += con;});
          resolve(newContent);
        },
        (err) => {reject(err);
        }
      );
    });
  }
}
 
fildFile(filePath);

ts 编译 (tsconfig-aot.json)

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./publish/src",
    "baseUrl": "./",
    "declaration": true,
    "importHelpers": true,
    "module": "es2015",
    "sourceMap": false,
    "target": "es2015",
    "types": ["node"]
  },
  "files": ["./src/temp_components/ng-kylin.module.ts"],
  "angularCompilerOptions": {
    "annotateForClosureCompiler": true,
    "strictMetadataEmit": true,
    "flatModuleOutFile": "index.js",
    "flatModuleId": "ng-kylin",
    "skipTemplateCodegen": true
  }
}

rollup 打包 (rollup-config.js)

import resolve from "rollup-plugin-node-resolve";
import replace from "rollup-plugin-replace";
 
const format = process.env.ROLLUP_FORMAT || "es";
 
let globals = {
  "@angular/animations": "ng.animations",
  "@angular/cdk": "ng.cdk",
  "@angular/core": "ng.core",
  "@angular/common": "ng.common",
  "@angular/compiler": "ng.compiler",
  "@angular/forms": "ng.forms",
  "@angular/platform-browser": "ng.platformBrowser",
  moment: "moment",
  "moment/locale/zh-cn": null,
  "rxjs/BehaviorSubject": "Rx",
  "rxjs/Observable": "Rx",
  "rxjs/Subject": "Rx",
  "rxjs/Subscription": "Rx",
  "rxjs/observable/fromPromise": "Rx.Observable",
  "rxjs/observable/forkJoin": "Rx.Observable",
  "rxjs/observable/fromEvent": "Rx.Observable",
  "rxjs/observable/merge": "Rx.Observable",
  "rxjs/observable/of": "Rx.Observable",
  "rxjs/operator/auditTime": "Rx.Observable.prototype",
  "rxjs/operator/catch": "Rx.Observable.prototype",
  "rxjs/operator/debounceTime": "Rx.Observable.prototype",
  "rxjs/operator/distinctUntilChanged": "Rx.Observable.prototype",
  "rxjs/operator/do": "Rx.Observable.prototype",
  "rxjs/operator/filter": "Rx.Observable.prototype",
  "rxjs/operator/finally": "Rx.Observable.prototype",
  "rxjs/operator/first": "Rx.Observable.prototype",
  "rxjs/operator/map": "Rx.Observable.prototype",
  "rxjs/operator/pluck": "Rx.Observable.prototype",
  "rxjs/operator/startWith": "Rx.Observable.prototype",
  "rxjs/operator/switchMap": "Rx.Observable.prototype",
  "rxjs/operator/takeUntil": "Rx.Observable.prototype",
  "rxjs/operator/throttleTime": "Rx.Observable.prototype",
};
 
if (format === "es") {
  globals = Object.assign(globals, {tslib: "tslib",});
}
 
let input;
let file;
 
switch (format) {
  case "es":
    input = "./publish/src/index.js";
    file = "./publish/esm15/index.js";
    break;
  case "umd":
    input = "./publish/esm5/index.js";
    file = "./publish/bundles/ng-kylin.umd.js";
    break;
  default:
    throw new Error(`format ${format} is not supported`);
}
 
export default {
  input,
  output: {
    file,
    format,
  },
  exports: "named",
  name: "ngKylin",
  plugins: [replace({ "import * as moment": "import moment"}), resolve()],
  external: Object.keys(globals),
  globals,
};

shell 脚本定义执行流程 (build.sh)

#!/usr/bin/env bash
 
rm -rf ./publish
 
cp -r src/app/components src/temp_components
 
node ./html.merge.js
 
echo 'Generating entry file using Angular compiler'
$(npm bin)/ngc -p tsconfig-aot.json
rm -rf src/temp_components
 
echo 'Bundling to es module'
export ROLLUP_FORMAT=es
$(npm bin)/rollup -c rollup-config.js
rm -rf publish/src/*.js
rm -rf publish/src/**/*.js
sed -e "s/from'.\//from '.\/src\//g" publish/src/index.d.ts > publish/index.d.ts
sed -e "s/\":\".\//\":\".\/src\//g" publish/src/index.metadata.json > publish/index.metadata.json
rm publish/src/index.d.ts publish/src/index.metadata.json
 
echo 'Transpiling es module to es5'
$(npm bin)/tsc --allowJs --importHelpers --target es5 --module es2015 --outDir publish/esm5 publish/esm15/index.js
 
echo 'Bundling to umd module'
export ROLLUP_FORMAT=umd
$(npm bin)/rollup -c rollup-config.js
 
echo 'Minifying umd module'
$(npm bin)/uglifyjs publish/bundles/ng-kylin.umd.js --output publish/bundles/ng-kylin.umd.min.js
 
echo 'Copying package.json'
cp package.json publish/package.json

至此，我的项目打包完结。