egg-view

Base view plugin for egg

it's a plugin that has been built-in for egg.

Install

1$ npm i egg-view --save

Usage

1// {app_root}/config/plugin.js
2exports.view = {
3  enable: true,
4  package: 'egg-view',
5};

Use a template engine

egg-view don't have build-in view engine, So you should choose a template engine like ejs, and install egg-view-ejs plugin.

You can choose a template engine first, link ejs, so we use egg-view-ejs plugin.

egg-view is in eggjs, so you just need configure egg-view-ejs.

1// config/plugin.js
2exports.ejs = {
3  enable: true,
4  package: 'egg-view-ejs',
5};

Configure the mapping, the file with .ejs extension will be rendered by ejs.

1// config/config.default.js
2exports.view = {
3  mapping: {
4    '.ejs': 'ejs',
5  },
6};

In controller, you can call ctx.render.

1module.exports = app => {
2  return class UserController extends app.Controller {
3    async list() {
4      const { ctx } = this;
5      await ctx.render('user.ejs');
6    }
7  };
8};

If you call ctx.renderString, you should specify viewEngine in viewOptions.

1module.exports = app => {
2  return class UserController extends app.Controller {
3    async list() {
4      const { ctx } = this;
5      ctx.body = await ctx.renderString('<%= user %>', { user: 'popomore' }, {
6        viewEngine: 'ejs',
7      });
8    }
9  };
10};

Use multiple view engine

egg-view support multiple view engine, so you can use more than one template engine in one application.

If you want add another template engine like nunjucks, then you can add egg-view-nunjucks plugin.

Configure the plugin and mapping

1// config/config.default.js
2exports.view = {
3  mapping: {
4    '.ejs': 'ejs',
5    '.nj': 'nunjucks',
6  },
7};

You can simply render the file with .nj extension.

1await ctx.render('user.nj');

How to write a view plugin

You can use egg-view' API to register a plugin.

View engine

Create a view engine class first, and implement render and renderString, if the template engine don't support, just throw an error. The view engine is context level, so it receive ctx in constructor.

1// lib/view.js
2module.exports = class MyView {
3  constructor(ctx) {
4    // do some initialize
5    // get the plugin config from `ctx.app.config`
6  }
7
8  async render(fullpath, locals) {
9    return myengine.render(fullpath, locals);
10  }
11
12  async renderString() { throw new Error('not implement'); }
13};

render and renderString support generator function, async function, or normal function return a promise.

If the template engine only support callback, you can wrap it by Promise.

1class MyView {
2  render(fullpath, locals) {
3    return new Promise((resolve, reject) => {
4      myengine.render(fullpath, locals, (err, result) => {
5        if (err) {
6          reject(err);
7        } else {
8          resolve(result);
9        }
10      });
11    });
12  }
13};

These methods receive three arguments, renderString will pass tpl as the first argument instead of name in render.

render(name, locals, viewOptions)

• name: the file path that can resolve from root (app/view by default)
• locals: data used by template
• viewOptions: the view options for each render, it can override the view default config in config/config.default.js. Plugin should implement it if it has config. When you implement view engine, you will receive this options from render, the options contain:
  • root: egg-view will resolve the name to full path, but seperating root and name in viewOptions.
  • name: the original name when call render
  • locals: the original locals when call render

renderString(tpl, locals, viewOptions)

• tpl: the template string instead of the file, using in renderString
• locals: same as render
• viewOptions: same as render

Register

After define a view engine, you can register it.

1// app.js
2module.exports = app => {
3  app.view.use('myName', require('./lib/view'));
4};

You can define a view engine name, normally it's a template name.

Configure

Define plugin name and depend on egg-view

1{
2  "eggPlugin": {
3    "name": "myName",
4    "dependencies": [ "view" ]
5  }
6}

Set default config in config/config.default.js, the name is equals to plugin name.

1exports.myName = {},

See some examples

• egg-view-ejs
• egg-view-nunjucks

Configuration

Root

Root is ${baseDir}/app/view by default, but you can define multiple directory, seperated by ,. egg-view will find a file from all root directories.

1module.exports = appInfo => {
2  const baseDir = appInfo.baseDir;
3  return {
4    view: {
5      root: `${baseDir}/app/view,${baseDir}/app/view2`
6    }
7  }
8}

defaultExtension

When render a file, you should specify a extension that let egg-view know whitch engine you want to use. However you can define defaultExtension without write the extension.

1// config/config.default.js
2exports.view = {
3  defaultExtension: '.html',
4};
5
6// controller
7module.exports = app => {
8  return class UserController extends app.Controller {
9    async list() {
10      const { ctx } = this;
11      // render user.html
12      await ctx.render('user');
13    }
14  };
15};

viewEngine and defaultViewEngine

If you are using renderString, you should specify viewEngine in view config, see example above.

However, you can define defaultViewEngine without set each time.

1// config/config.default.js
2exports.view = {
3  defaultViewEngine: 'ejs',
4};

see config/config.default.js for more detail.

Questions & Suggestions

Please open an issue here.

License

MIT