├── .github └── workflows │ └── ci.yml ├── .gitignore ├── LICENSE ├── README.md ├── metaline.js ├── package.json ├── renovate.json └── test.js /.github/workflows/ci.yml: -------------------------------------------------------------------------------- 1 | name: ci 2 | 3 | on: 4 | push: 5 | paths-ignore: 6 | - 'docs/**' 7 | - '*.md' 8 | pull_request: 9 | paths-ignore: 10 | - 'docs/**' 11 | - '*.md' 12 | 13 | jobs: 14 | test: 15 | runs-on: ubuntu-latest 16 | 17 | strategy: 18 | matrix: 19 | node-version: [18.x, 20.x] 20 | steps: 21 | - uses: actions/checkout@v3 22 | 23 | - name: Use Node.js 24 | uses: actions/setup-node@v2 25 | with: 26 | node-version: ${{ matrix.node-version }} 27 | 28 | - name: Install 29 | run: | 30 | npm install 31 | 32 | - name: Run tests 33 | run: | 34 | npm run test 35 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | # Logs 2 | logs 3 | *.log 4 | npm-debug.log* 5 | yarn-debug.log* 6 | yarn-error.log* 7 | lerna-debug.log* 8 | .pnpm-debug.log* 9 | 10 | # Diagnostic reports (https://nodejs.org/api/report.html) 11 | report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json 12 | 13 | # Runtime data 14 | pids 15 | *.pid 16 | *.seed 17 | *.pid.lock 18 | 19 | # Directory for instrumented libs generated by jscoverage/JSCover 20 | lib-cov 21 | 22 | # Coverage directory used by tools like istanbul 23 | coverage 24 | *.lcov 25 | 26 | # nyc test coverage 27 | .nyc_output 28 | 29 | # Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files) 30 | .grunt 31 | 32 | # Bower dependency directory (https://bower.io/) 33 | bower_components 34 | 35 | # node-waf configuration 36 | .lock-wscript 37 | 38 | # Compiled binary addons (https://nodejs.org/api/addons.html) 39 | build/Release 40 | 41 | # Dependency directories 42 | node_modules/ 43 | jspm_packages/ 44 | 45 | # Snowpack dependency directory (https://snowpack.dev/) 46 | web_modules/ 47 | 48 | # TypeScript cache 49 | *.tsbuildinfo 50 | 51 | # Optional npm cache directory 52 | .npm 53 | 54 | # Optional eslint cache 55 | .eslintcache 56 | 57 | # Optional stylelint cache 58 | .stylelintcache 59 | 60 | # Microbundle cache 61 | .rpt2_cache/ 62 | .rts2_cache_cjs/ 63 | .rts2_cache_es/ 64 | .rts2_cache_umd/ 65 | 66 | # Optional REPL history 67 | .node_repl_history 68 | 69 | # Output of 'npm pack' 70 | *.tgz 71 | 72 | # Yarn Integrity file 73 | .yarn-integrity 74 | 75 | # dotenv environment variable files 76 | .env 77 | .env.development.local 78 | .env.test.local 79 | .env.production.local 80 | .env.local 81 | 82 | # parcel-bundler cache (https://parceljs.org/) 83 | .cache 84 | .parcel-cache 85 | 86 | # Next.js build output 87 | .next 88 | out 89 | 90 | # Nuxt.js build / generate output 91 | .nuxt 92 | dist 93 | 94 | # Gatsby files 95 | .cache/ 96 | # Comment in the public line in if your project uses Gatsby and not Next.js 97 | # https://nextjs.org/blog/next-9-1#public-directory-support 98 | # public 99 | 100 | # vuepress build output 101 | .vuepress/dist 102 | 103 | # vuepress v2.x temp and cache directory 104 | .temp 105 | .cache 106 | 107 | # Docusaurus cache and generated files 108 | .docusaurus 109 | 110 | # Serverless directories 111 | .serverless/ 112 | 113 | # FuseBox cache 114 | .fusebox/ 115 | 116 | # DynamoDB Local files 117 | .dynamodb/ 118 | 119 | # TernJS port file 120 | .tern-port 121 | 122 | # Stores VSCode versions used for testing VSCode extensions 123 | .vscode-test 124 | 125 | # yarn v2 126 | .yarn/cache 127 | .yarn/unplugged 128 | .yarn/build-state.yml 129 | .yarn/install-state.gz 130 | .pnp.* 131 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # metaline 2 | 3 | A tiny language to write mapping functions as strings. 4 | 5 | ## Install 6 | 7 | ```bash 8 | npm i metaline 9 | ``` 10 | 11 | ## Example syntax 12 | 13 | The string `where.id.in.$>#id;limit:99` generates the equivalent function of: 14 | 15 | ```js 16 | function transform (input) { 17 | return { 18 | where: { 19 | id: { 20 | in: input.map((i) => i.id) 21 | } 22 | }, 23 | limit: 99 24 | } 25 | } 26 | ``` 27 | 28 | The string `$>id.#directoryId` generates the equivalent function of: 29 | 30 | ```js 31 | function transform (input) { 32 | return input.map((t) => { 33 | return { 34 | id: t.directoryId 35 | } 36 | }) 37 | } 38 | ``` 39 | 40 | 41 | ## Language Tokens 42 | 43 | * `.` separate properties in an object 44 | * `$` the input 45 | * `$>` loop over the input 46 | * `#` access the following input property 47 | 48 | ## License 49 | 50 | Apache-2.0 51 | -------------------------------------------------------------------------------- /metaline.js: -------------------------------------------------------------------------------- 1 | 'use strict' 2 | 3 | function deepmergeArray (options) { 4 | const deepmerge = options.deepmerge 5 | return function (target, source) { 6 | let i = 0 7 | const result = new Array(target.length) 8 | for (i = 0; i < target.length; ++i) { 9 | // This will throw if the items are not equal in length 10 | // but this cannot happen with the current usage 11 | result[i] = deepmerge(target[i], source[i]) 12 | } 13 | return result 14 | } 15 | } 16 | 17 | const deepmerge = require('@fastify/deepmerge')({ 18 | mergeArray: deepmergeArray 19 | }) 20 | 21 | class ParseError extends Error { 22 | constructor (token, position) { 23 | super(`Unexpected token \`${token}\` at position ${position}`) 24 | } 25 | } 26 | 27 | // TODO this shold be a parser that generates a function 28 | function parsePhrase (phrase) { 29 | const path = [] 30 | 31 | let startKey = 0 32 | let i = 0 33 | for (; i < phrase.length; i++) { 34 | if (phrase.charCodeAt(i) === 46) { // . 35 | if (i === 0) { 36 | throw new ParseError(phrase[i], i) 37 | } 38 | path.push({ 39 | type: 'key', 40 | key: phrase.slice(startKey, i) 41 | }) 42 | startKey = i + 1 43 | } 44 | 45 | if (phrase.charCodeAt(i) === 36) { // $ 46 | if (startKey !== i) { 47 | throw new ParseError(phrase[i], i) 48 | } 49 | if (phrase.charCodeAt(i + 1) === 62) { // > 50 | path.push({ 51 | type: 'loop' 52 | }) 53 | i += 2 54 | startKey = i 55 | } else { 56 | path.push({ 57 | type: 'input' 58 | }) 59 | } 60 | } 61 | 62 | if (phrase.charCodeAt(i) === 35) { // # 63 | if (startKey !== i) { 64 | throw new ParseError(phrase[i], i) 65 | } 66 | path.push({ 67 | type: 'property', 68 | key: phrase.slice(i + 1) 69 | }) 70 | } 71 | 72 | if (phrase.charCodeAt(i) === 58) { // : 73 | const sliced = phrase.slice(i + 1) 74 | let value = parseFloat(sliced) 75 | if (isNaN(value)) { 76 | value = parseInt(sliced) 77 | if (isNaN(value)) { 78 | value = sliced 79 | } 80 | } 81 | path.push({ 82 | type: 'value', 83 | key: phrase.slice(startKey, i), 84 | value 85 | }) 86 | break 87 | } 88 | } 89 | 90 | return function (input) { 91 | return transformPhrase(input, path) 92 | } 93 | 94 | function transformPhrase (input, path) { 95 | let out = {} 96 | let obj = out 97 | let currentKey = null 98 | for (let i = 0; i < path.length; i++) { 99 | const chunk = path[i] 100 | if (chunk.type === 'input') { 101 | if (currentKey) { 102 | obj[currentKey] = input 103 | } else { 104 | out = input 105 | } 106 | } else if (chunk.type === 'key') { 107 | if (currentKey) { 108 | obj[currentKey] = {} 109 | obj = obj[currentKey] 110 | } 111 | currentKey = chunk.key 112 | } else if (chunk.type === 'value') { 113 | const dest = { 114 | [chunk.key]: chunk.value 115 | } 116 | if (currentKey) { 117 | obj[currentKey] = dest 118 | } else { 119 | out = dest 120 | } 121 | } else if (chunk.type === 'property') { 122 | if (currentKey) { 123 | obj[currentKey] = input[chunk.key] 124 | } else { 125 | out = input[chunk.key] 126 | } 127 | } else if (chunk.type === 'loop') { 128 | const remaining = path.slice(i + 1) 129 | const value = [...new Set(input.map(item => { 130 | return transformPhrase(item, remaining) 131 | }).flat())] 132 | 133 | if (currentKey) { 134 | obj[currentKey] = value 135 | } else { 136 | out = value 137 | } 138 | break 139 | } 140 | } 141 | return out 142 | } 143 | } 144 | 145 | function metaline (str) { 146 | const phrases = str.split(';') 147 | 148 | const fns = phrases.map(parsePhrase) 149 | 150 | function transform (input) { 151 | let out = {} 152 | for (const fn of fns) { 153 | out = deepmerge(out, fn(input)) 154 | } 155 | return out 156 | } 157 | 158 | return transform 159 | } 160 | 161 | module.exports = metaline 162 | module.exports.metaline = metaline 163 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "metaline", 3 | "version": "1.1.0", 4 | "description": "A tiny language to write mapping functions as strings", 5 | "main": "metaline.js", 6 | "scripts": { 7 | "test": "standard | snazzy && c8 node --test" 8 | }, 9 | "keywords": [ 10 | "mapping", 11 | "function", 12 | "string", 13 | "line" 14 | ], 15 | "author": "Matteo Collina ", 16 | "license": "Apache-2.0", 17 | "devDependencies": { 18 | "c8": "^9.0.0", 19 | "snazzy": "^9.0.0", 20 | "standard": "^17.1.0" 21 | }, 22 | "dependencies": { 23 | "@fastify/deepmerge": "^2.0.0" 24 | } 25 | } 26 | -------------------------------------------------------------------------------- /renovate.json: -------------------------------------------------------------------------------- 1 | { 2 | "$schema": "https://docs.renovatebot.com/renovate-schema.json", 3 | "extends": [ 4 | "config:base" 5 | ] 6 | } 7 | -------------------------------------------------------------------------------- /test.js: -------------------------------------------------------------------------------- 1 | 'use strict' 2 | 3 | const { test } = require('node:test') 4 | const { deepEqual, throws } = require('node:assert/strict') 5 | const metaline = require('./metaline.js') 6 | 7 | function buildTest (str, input, output, opts = {}) { 8 | test(str, opts, t => { 9 | const fn = metaline(str) 10 | deepEqual(fn(input), output) 11 | }) 12 | } 13 | 14 | buildTest('where.directorId.in.$', [1, 2], { where: { directorId: { in: [1, 2] } } }) 15 | buildTest('limit:99', null, { limit: 99 }) 16 | buildTest('limit:foo', null, { limit: 'foo' }) 17 | buildTest('limit:99.9', null, { limit: 99.9 }) 18 | buildTest('a.limit:99.9', null, { a: { limit: 99.9 } }) 19 | buildTest('$', 1, 1) 20 | buildTest('where.directorId.in.$;limit:99', [1, 2], { where: { directorId: { in: [1, 2] } }, limit: 99 }) 21 | buildTest('$>#id', [{ id: 1 }, { id: 2 }], [1, 2]) 22 | buildTest('where.id.in.$>#id;limit:99', [{ id: 1 }, { id: 2 }], { where: { id: { in: [1, 2] } }, limit: 99 }) 23 | buildTest('$>id.#directorId', [{ directorId: 1 }, { directorId: 2 }], [{ id: 1 }, { id: 2 }]) 24 | buildTest('$>id.#directorId;$>foo.#bar', [{ directorId: 1, bar: 2 }, { directorId: 2, bar: 3 }], [{ id: 1, foo: 2 }, { id: 2, foo: 3 }]) 25 | buildTest('$>#movieIds', [ 26 | { name: 'Odeon', id: '90', movieIds: ['10', '12'] }, 27 | { name: 'Main Theatre', id: '92', movieIds: ['12', '10'] } 28 | ], ['10', '12']) 29 | 30 | test('parsing errors', t => { 31 | throws(() => metaline('.#'), { message: 'Unexpected token `.` at position 0' }) 32 | throws(() => metaline('foo#'), { message: 'Unexpected token `#` at position 3' }) 33 | throws(() => metaline('foo$'), { message: 'Unexpected token `$` at position 3' }) 34 | }) 35 | --------------------------------------------------------------------------------