104 lines
3.1 KiB
Markdown
104 lines
3.1 KiB
Markdown
# argument-parser
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This module parses the command line arguments into a JavaScript object, and verifies that they match the given specification. It checks that all required options are set, that no unknown options are used, and optionally that the arguments match a given pattern.
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The main goal is to keep all the complexity and error handling inside this module, so that all command line applications only need to provide a couple lines of specification and do not have to worry about verifying the input or checking for `undefined`.
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## Installation
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For this tool to work, the TypeScript compiler must be globally installed:
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```bash
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sudo npm install -g typescript
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```
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In the project where you want to use this library, add the following to your `package.json` file:
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```json
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{
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"dependencies": {
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"argument-parser": "git+https://git.jedipedia.net/swtor/argument-parser.git"
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}
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}
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```
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Then run:
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```bash
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npm install
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```
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## Usage
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This example shows how to use this module to check the arguments against a specification.
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```ts
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#!/usr/bin/env node
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import parseArguments from 'argument-parser';
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/**
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* Check that arguments match the specification and stop execution on error.
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* Then parse the arguments into the `args` object.
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* The `fail()` function can be used to print an error message and will then
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* terminate execution.
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* Two options are allowed: --input and --size, or their short forms -i and -s.
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* --input is required, while --size is optional and defaults to "0".
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*/
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const { args, fail } = parseArguments({
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input: {
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short: 'i',
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description: 'Path to the input file'
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},
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size: {
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default: '0',
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short: 's',
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description: 'Size of the file, must be a non-negative integer',
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verify: str => str.match(/^[0-9]+$/) !== null
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}
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});
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try {
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console.log(args.input, args.size);
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//Do something based on the arguments...
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} catch (error) {
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fail(`Error during execution: ${String(error)}`);
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}
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```
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When called correctly from the command line, it prints the following:
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```bash
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$ ./index.js --input data.bin --size 1024
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data.bin 1024
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```
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In case of an error, it prints an error message as well as the correct usage instructions, and then terminates with a non-zero exit code.
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```bash
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$ node index.js --wrong-option foobar
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Error: Unknown option "--wrong-option".
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Usage: ./index.js [options]
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OPTIONS
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-i, --input <value>
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Path to the input file
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[-s, --s <value>], defaults to "0"
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Size of the file, must be a non-negative integer
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```
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## License
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Copyright (C) 2018-2019 Jedipedia.net
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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