fx/index.js
2018-01-26 09:35:58 +07:00

69 lines
1.4 KiB
JavaScript
Executable File

#!/usr/bin/env node
'use strict';
const meow = require('meow')
const stdin = require('get-stdin')
const cardinal = require('cardinal')
const theme = require('cardinal/themes/tomorrow-night')
const cli = meow(`
Usage
$ fx [code ...]
Examples
$ echo '{"key": "value"}' | fx 'x => x.key'
"value"
$ echo '[1,2,3]' | fx 'this.map(x => x * 2)'
[2, 4, 6]
$ echo '{"items": ["one", "two"]}' | fx 'this.items' 'this[1]'
"two"
$ echo '{"count": 0}' | fx '{...this, count: 1}'
{"count": 1}
`)
const highlight = process.stdout.isTTY ? cardinal.highlight : x => x
async function main() {
const text = await stdin()
if (text === '') {
cli.showHelp()
}
const json = JSON.parse(text)
const result = cli.input.reduce(reduce, json)
if (typeof result === 'undefined') {
console.log(undefined)
} else {
const text = JSON.stringify(result, null, 4)
console.log(highlight(text, {theme}))
}
}
function reduce(json, code) {
if (/^\w+\s*=>/.test(code)) {
const fx = eval(code)
return fx(json)
} else if (/yield/.test(code)) {
const fx = eval(`
function fn() {
const gen = (function*(){
${code.replace(/\\\n/g, '')}
}).call(this)
return [...gen]
}; fn
`)
return fx.call(json)
} else {
const fx = eval(`function fn() { return ${code} }; fn`)
return fx.call(json)
}
}
main()