ELS – The Ember Language Server - Speaker Deck

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ELS the Ember Language Server

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Turbo87 TobiasBieniek

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simplabs based in Munich consulting all over ! * Stickers available after the talk

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Disclaimer this talk contains simplified code examples! the real code is available at   https://github.com/emberwatch/ember-language-server

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What text editor do you use? " # $ % $ & ' ( ) * " *

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No content

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Goto Class

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Goto Definition

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IntelliJ-only

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vim Emacs VS Code IntelliJ JavaScript ❓ ❓ ❓ ❓ CSS ❓ ❓ ❓ ❓ Ember.js ❓ ❓ ❓ ❓ Rust ❓ ❓ ❓ ❓

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JavaScript ✅ CSS ✅ Ember.js ✅ Rust ✅ vim ✅ Emacs ✅ VS Code ✅ IntelliJ ✅

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JavaScript javascript- typescript- langserver CSS vscode-css- languageserver Ember.js ember-languageserver Rust rust-languageserver vim vim-lsp Emacs emacs-lsp VS Code builtin! IntelliJ

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HTTP JSON API

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ELS JSON-RPC Language Server Protocol HTTP JSON API

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JSON-RPC 2.0 Request {  "jsonrpc": "2.0",  "id": 42,  "method": "add",  "params": {  "a": 1,  "b": 2,  },  } Response {  "jsonrpc": "2.0",  "id": 42,  "result": 3,  "error": null,  }

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vscode-languageserver

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Syntax Highlighting

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Syntax Highlighting (sorry, not responsible for that...) https://github.com/Microsoft/language-server-protocol/issues/33#issuecomment-231883169

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Autocomplete

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Request {  "method": "textDocument/completion",  "params": {  "textDocument": {  "uri": "file: ///Users/tbieniek/Code/crates.io/app/templates/index.hbs",  },  "position": {  "line": 5,  "character": 18,  },  },  }

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import URI from 'vscode-uri';  let uri = URI.parse(  'file: ///Users/tbieniek/Code/crates.io/app/templates/index.hbs'  ) let path = uri.fsPath; // -> /Users/tbieniek/Code/crates.io/app/templates/index.hbs

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import fs from 'fs'; let content = fs.readFileSync( '/Users/tbieniek/Code/crates.io/app/templates/index.hbs', { encoding: 'utf-8' }, ); let lines = content.split('\n'); let line = line[5]; let character = line[18]; // -> a

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import fs from 'fs'; import { preprocess } from '@glimmer/syntax'; let content = fs.readFileSync( '/Users/tbieniek/Code/crates.io/app/templates/index.hbs', { encoding: 'utf-8' }, ); let ast = preprocess(content); // -> Abstract Syntax T ree

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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AST Explorer https://astexplorer.net

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{{button onclick=(a)}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression Cursor

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path: { type: 'PathExpression', original: 'a', this: false, parts: [ 'a', ], data: false, loc: { start: { line: 5, column: 18, }, end: { line: 5, column: 19, }, }, } Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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path: { type: 'PathExpression', original: 'a', this: false, parts: [ 'a', ], data: false, loc: { start: { line: 5, column: 18, }, end: { line: 5, column: 19, }, }, } position: {  line: 5,  character: 18,  } Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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let node = findNodeAtPosition(ast, position); let isSubExpressionPath = ( node.type === 'PathExpression' && node.parent.type === 'SubExpression' ); if (isSubExpressionPath) { return SUB_EXPRESSION_HELPERS; }

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const SUB_EXPRESSION_HELPER_NAMES = [ 'action', 'component', 'concat', 'get', 'if', 'unless', ]; const SUB_EXPRESSION_HELPERS = SUB_EXPRESSION_HELPER_NAMES  .map(name => ({ label: name, kind: CompletionItemKind.Function, }));

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Autocomplete ✅

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Autocomplete #2

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import path from 'path'; import findUp from 'find-up'; let projectRoot = findUp.sync('ember-cli-build.js', { cwd: path.dirname( '/Users/tbieniek/Code/crates.io/app/templates/index.hbs' ), }); // -> /Users/tbieniek/Code/crates.io

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import glob from 'fast-glob'; let components = glob.sync(['**/*.js'], {  cwd: `${projectRoot}/app/components`,  }); let templates = glob.sync(['**/*.hbs'], {  cwd: `${projectRoot}/app/templates/components`,  });

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import glob from 'fast-glob'; let components = glob.sync(['**/*.js'], {  cwd: `${projectRoot}/app/components`,  }); let templates = glob.sync(['**/*.hbs'], {  cwd: `${projectRoot}/app/templates/components`,  }); let names = components .concat(templates) .map(filePath => stripExtension(filePath));

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import glob from 'fast-glob'; let components = glob.sync(['**/*.js'], {  cwd: `${projectRoot}/app/components`,  }); let templates = glob.sync(['**/*.hbs'], {  cwd: `${projectRoot}/app/templates/components`,  }); let names = components .concat(templates) .map(filePath => stripExtension(filePath)); let uniqueNames = Array.from(new Set(names));

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let names = components .concat(templates) .map(filePath => stripExtension(filePath)); let uniqueNames = Array.from(new Set(names)); return uniqueNames.map(name => ({ label: name, kind: CompletionItemKind.Class, }));

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Autocomplete #2 ✅

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Goto Definition

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Request {  "method": "textDocument/definition",  "params": {  "textDocument": {  "uri": "file: ///Users/tbieniek/Code/crates.io/app/templates/crate.hbs",  },  "position": {  "line": 92,  "character": 14,  },  },  }

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{{crate-readme  rendered=crate.readme}} Program -> MustacheStatement -> PathExpression -> Hash -> HashPair -> SubExpression -> PathExpression

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let node = findNodeAtPosition(ast, position); let isMustacheStatementPath = ( node.type === 'PathExpression' && node.parent.type === 'MustacheStatement' ); if (!isMustacheStatementPath) { return; }

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import path from 'path'; import findUp from 'find-up'; let projectRoot = findUp.sync('ember-cli-build.js', { cwd: path.dirname( '/Users/tbieniek/Code/crates.io/app/templates/crate.hbs' ), }); // -> /Users/tbieniek/Code/crates.io

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import URI from 'vscode-uri'; let componentPath = `${projectRoot}/app/components/${node.original}.js`; if (fs.existsSync(componentPath)) { results.push({ uri: URI.file(componentPath), range: { start: ..., end: ... }, }); }

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What else can  we build with this?

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{{#link-to "index"}}Home{{/link-to}} • app/controllers/index.js • app/routes/index.js • app/templates/index.hbs

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import DS from 'ember-data'; export default DS.Model.extend({ crates: DS.hasMany('crate'), }); • app/adapters/crate.js • app/models/crate.js • app/serializers/crate.js

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import Component from '@ember/component'; import { inject as service } from '@ember/service'; export default Component.extend({ session: service('session'), }); • app/services/session.js

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{{t "my-name-is"}} • translations/de.json • translations/en.json • translations/fr.json • translations/nl.json

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Caveats (roadblocks and deviations)

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Compiler vs. Editor

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Compiler > must produce 100% correct output > expects 100% valid input

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Editor > is allowed to produce incomplete output > should handle incomplete/invalid input

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@glimmer/syntax > written for the template compiler > can not handle incomplete/invalid input {{#link-to "|

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ELS Editor Support

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ELS Editor Support > VSCode ... done (vscode-ember extension) > Atom ... done (ide-ember package) > emacs ... work-in-progress > vim ... )

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Wishlist (not yet supported by LSP)

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File Type Icons

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Goto Related File from the crates controller

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Goto Related File > cycle through controller, route, template > or component and template > or model, adapter, serializer > or to the related test file

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Inline Translations

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emberwatch/ember-language-server #topic-editors

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ELS the Ember Language Server Thanks!