摘要：模塊庫開發(fā)實(shí)例隨著前端框架的誕生，也會(huì)隨之出現(xiàn)一些組件庫，方便日常業(yè)務(wù)開發(fā)。在瀏覽器中，渲染是將模型映射到視圖的過程。然而視圖可以是頁面中的段落表單按鈕等其他元素，這些頁面元素內(nèi)部使用來表示。

隨著前端框架的誕生，也會(huì)隨之出現(xiàn)一些組件庫，方便日常業(yè)務(wù)開發(fā)。今天就聊聊angular4組件庫開發(fā)流程。

下圖是button組件的基礎(chǔ)文件。

nk-button.component.ts為該組件的核心文件，看看代碼：

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 = [];

  @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() {
  }

  /**
   *設(shè)置class屬性
   */
  _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);
    });
  }
}

針對(duì)核心概念ElementRef、Renderer2、ViewEncapsulation做簡要說明：

在應(yīng)用層直接操作 DOM，就會(huì)造成應(yīng)用層與渲染層之間強(qiáng)耦合，通過 ElementRef 我們就可以封裝不同平臺(tái)下視圖層中的 native 元素 (在瀏覽器環(huán)境中，native 元素通常是指 DOM 元素)，最后借助于 Angular 提供的強(qiáng)大的依賴注入特性，我們就可以輕松地訪問到 native 元素。

參考鏈接

渲染器是 Angular 為我們提供的一種內(nèi)置服務(wù)，用于執(zhí)行 UI 渲染操作。在瀏覽器中，渲染是將模型映射到視圖的過程。模型的值可以是 JavaScript 中的原始數(shù)據(jù)類型、對(duì)象、數(shù)組或其它的數(shù)據(jù)對(duì)象。然而視圖可以是頁面中的段落、表單、按鈕等其他元素，這些頁面元素內(nèi)部使用DOM來表示。

參考鏈接

ViewEncapsulation 允許設(shè)置三個(gè)可選的值：

ViewEncapsulation.Emulated - 無 Shadow DOM，但是通過 Angular 提供的樣式包裝機(jī)制來封裝組件，使得組件的樣式不受外部影響。這是 Angular 的默認(rèn)設(shè)置。

ViewEncapsulation.Native - 使用原生的 Shadow DOM 特性

ViewEncapsulation.None - 無 Shadow DOM，并且也無樣式包裝

參考鏈接

button組件創(chuàng)建思路：

針對(duì)button我們只需修改其樣式，因此在這里創(chuàng)建屬性指令

提供屬性接口

根據(jù)其傳入的屬性值動(dòng)態(tài)渲染DOM

至此，最簡單的button就開發(fā)結(jié)束。

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!");
      })
    });

}

/**
 * 轉(zhuǎn)換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);

{
  "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
  }
}

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,
}

#!/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，項(xiàng)目打包結(jié)束。

源碼