fx/npm/index.js
2023-04-19 12:11:54 +02:00

548 lines
13 KiB
JavaScript

#!/usr/bin/env node
'use strict'
void async function main() {
const process = await import('node:process')
let flagHelp = false
let flagRaw = false
let flagSlurp = false
const args = []
for (const arg of process.argv.slice(2)) {
if (arg === '--help' || arg === '-h') flagHelp = true
else if (arg === '--raw' || arg === '-r') flagRaw = true
else if (arg === '--slurp' || arg === '-s') flagSlurp = true
else if (arg === '-rs' || arg === '-sr') flagRaw = flagSlurp = true
else args.push(arg)
}
if (flagHelp || (args.length === 0 && process.stdin.isTTY))
return printUsage()
const stdin = await readStdinGenerator()
const input = flagRaw ? readLine(stdin) : parseJson(stdin)
if (flagSlurp) {
const array = []
for (const json of input) {
array.push(json)
}
await runTransforms(array, args)
} else {
for (const json of input) {
await runTransforms(json, args)
}
}
}()
const skip = Symbol('skip')
async function runTransforms(json, args) {
const process = await import('node:process')
let i, code, output = json
for ([i, code] of args.entries()) try {
output = await transform(output, code)
} catch (err) {
printErr(err)
process.exit(1)
}
if (typeof output === 'undefined')
console.error('undefined')
else if (typeof output === 'string')
console.log(output)
else if (output === skip)
return
else
console.log(stringify(output, process.stdout.isTTY))
function printErr(err) {
let pre = args.slice(0, i).join(' ')
let post = args.slice(i + 1).join(' ')
if (pre.length > 20) pre = '...' + pre.substring(pre.length - 20)
if (post.length > 20) post = post.substring(0, 20) + '...'
console.error(
`\n ${pre} ${code} ${post}\n` +
` ${' '.repeat(pre.length + 1)}${'^'.repeat(code.length)}\n` +
`\n${err.stack || err}`
)
}
}
async function transform(json, code) {
if ('.' === code)
return json
if ('?' === code)
return Object.keys(json)
if (/^(\.\w*)+\[]/.test(code))
return eval(`(function () {
return (${fold(code.split('[]'))})(this)
})`).call(json)
if (/^\.\[/.test(code))
return eval(`(function () {
return this${code.substring(1)}
})`).call(json)
if (/^\./.test(code))
return eval(`(function () {
return this${code}
})`).call(json)
if (/^map\(.+?\)$/.test(code)) {
let s = code.substring(4, code.length - 1)
if (s[0] === '.') s = 'x' + s
return eval(`(function () {
return this.map((x, i) => apply(${s}, x, i))
})`).call(json)
}
const fn = eval(`(function () {
return ${code}
})`).call(json)
return apply(fn, json)
function apply(fn, ...args) {
if (typeof fn === 'function') return fn(...args)
return fn
}
function fold(s) {
if (s.length === 1)
return 'x => x' + s[0]
let obj = s.shift()
obj = obj === '.' ? 'x' : 'x' + obj
return `x => Object.values(${obj}).flatMap(${fold(s)})`
}
function uniq(array) {
return [...new Set(array)]
}
function sort(array) {
return array.sort()
}
function groupBy(keyOrFunction) {
return array => {
const grouped = {}
for (const item of array) {
const key = typeof keyOrFunction === 'function'
? keyOrFunction(item)
: item[keyOrFunction]
if (!grouped.hasOwnProperty(key))
grouped[key] = []
grouped[key].push(item)
}
return grouped
}
}
}
async function readStdinGenerator() {
const fs = await import('node:fs')
const {Buffer} = await import('node:buffer')
const {StringDecoder} = await import('node:string_decoder')
const decoder = new StringDecoder('utf8')
return function* () {
while (true) {
const buffer = Buffer.alloc(4_096)
let bytesRead
try {
bytesRead = fs.readSync(0, buffer, 0, buffer.length, null)
} catch (e) {
if (e.code === 'EAGAIN' || e.code === 'EWOULDBLOCK') {
sleepSync(10)
continue
}
if (e.code === 'EOF') break
throw e
}
if (bytesRead === 0) break
for (const ch of decoder.write(buffer.subarray(0, bytesRead)))
yield ch
}
for (const ch of decoder.end())
yield ch
}()
}
function sleepSync(ms) {
Atomics.wait(new Int32Array(new SharedArrayBuffer(4)), 0, 0, ms)
}
function* readLine(stdin) {
let buffer = ''
for (const ch of stdin) {
if (ch === '\n') {
yield buffer
buffer = ''
} else {
buffer += ch
}
}
return buffer
}
function* parseJson(stdin) {
let lineNumber = 1, buffer = '', lastChar, done = false
function next() {
({value: lastChar, done} = stdin.next())
if (lastChar === '\n') lineNumber++
buffer += (lastChar || '')
if (buffer.length > 100) buffer = buffer.slice(-40)
}
next()
while (!done) {
const value = parseValue()
expectValue(value)
yield value
}
function parseValue() {
skipWhitespace()
const value =
parseString() ??
parseNumber() ??
parseObject() ??
parseArray() ??
parseKeyword('true', true) ??
parseKeyword('false', false) ??
parseKeyword('null', null)
skipWhitespace()
return value
}
function parseString() {
if (lastChar !== '"') return
let str = ''
let escaped = false
while (true) {
next()
if (escaped) {
if (lastChar === 'u') {
let unicode = ''
for (let i = 0; i < 4; i++) {
next()
if (!isHexDigit(lastChar)) {
throw new SyntaxError(errorSnippet(`Invalid Unicode escape sequence '\\u${unicode}${lastChar}'`))
}
unicode += lastChar
}
str += String.fromCharCode(parseInt(unicode, 16))
} else {
const escapedChar = {
'"': '"',
'\\': '\\',
'/': '/',
'b': '\b',
'f': '\f',
'n': '\n',
'r': '\r',
't': '\t'
}[lastChar]
if (!escapedChar) {
throw new SyntaxError(errorSnippet())
}
str += escapedChar
}
escaped = false
} else if (lastChar === '\\') {
escaped = true
} else if (lastChar === '"') {
break
} else if (lastChar === undefined) {
throw new SyntaxError(errorSnippet())
} else {
str += lastChar
}
}
next()
return str
}
function parseNumber() {
if (!isDigit(lastChar) && lastChar !== '-') return
let numStr = ''
if (lastChar === '-') {
numStr += lastChar
next()
if (!isDigit(lastChar)) {
throw new SyntaxError(errorSnippet())
}
}
if (lastChar === '0') {
numStr += lastChar
next()
} else {
while (isDigit(lastChar)) {
numStr += lastChar
next()
}
}
if (lastChar === '.') {
numStr += lastChar
next()
if (!isDigit(lastChar)) {
throw new SyntaxError(errorSnippet())
}
while (isDigit(lastChar)) {
numStr += lastChar
next()
}
}
if (lastChar === 'e' || lastChar === 'E') {
numStr += lastChar
next()
if (lastChar === '+' || lastChar === '-') {
numStr += lastChar
next()
}
if (!isDigit(lastChar)) {
throw new SyntaxError(errorSnippet())
}
while (isDigit(lastChar)) {
numStr += lastChar
next()
}
}
return isInteger(numStr) ? toSafeNumber(numStr) : parseFloat(numStr)
}
function parseObject() {
if (lastChar !== '{') return
next()
skipWhitespace()
const obj = {}
if (lastChar === '}') {
next()
return obj
}
while (true) {
if (lastChar !== '"') {
throw new SyntaxError(errorSnippet())
}
const key = parseString()
skipWhitespace()
if (lastChar !== ':') {
throw new SyntaxError(errorSnippet())
}
next()
const value = parseValue()
expectValue(value)
obj[key] = value
skipWhitespace()
if (lastChar === '}') {
next()
return obj
} else if (lastChar === ',') {
next()
skipWhitespace()
if (lastChar === '}') {
next()
return obj
}
} else {
throw new SyntaxError(errorSnippet())
}
}
}
function parseArray() {
if (lastChar !== '[') return
next()
skipWhitespace()
const array = []
if (lastChar === ']') {
next()
return array
}
while (true) {
const value = parseValue()
expectValue(value)
array.push(value)
skipWhitespace()
if (lastChar === ']') {
next()
return array
} else if (lastChar === ',') {
next()
skipWhitespace()
if (lastChar === ']') {
next()
return array
}
} else {
throw new SyntaxError(errorSnippet())
}
}
}
function parseKeyword(name, value) {
if (lastChar !== name[0]) return
for (let i = 1; i < name.length; i++) {
next()
if (lastChar !== name[i]) {
throw new SyntaxError(errorSnippet())
}
}
next()
if (isWhitespace(lastChar) || lastChar === ',' || lastChar === '}' || lastChar === ']' || lastChar === undefined) {
return value
}
throw new SyntaxError(errorSnippet())
}
function skipWhitespace() {
while (isWhitespace(lastChar)) {
next()
}
skipComment()
}
function skipComment() {
if (lastChar === '/') {
next()
if (lastChar === '/') {
while (!done && lastChar !== '\n') {
next()
}
skipWhitespace()
} else if (lastChar === '*') {
while (!done) {
next()
if (lastChar === '*') {
next()
if (lastChar === '/') {
next()
break
}
}
}
skipWhitespace()
} else {
throw new SyntaxError(errorSnippet())
}
}
}
function isWhitespace(ch) {
return ch === ' ' || ch === '\n' || ch === '\t' || ch === '\r'
}
function isHexDigit(ch) {
return (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F')
}
function isDigit(ch) {
return ch >= '0' && ch <= '9'
}
function isInteger(value) {
return /^-?[0-9]+$/.test(value)
}
function toSafeNumber(str) {
const maxSafeInteger = Number.MAX_SAFE_INTEGER
const minSafeInteger = Number.MIN_SAFE_INTEGER
const num = BigInt(str)
return num >= minSafeInteger && num <= maxSafeInteger ? Number(num) : num
}
function expectValue(value) {
if (value === undefined) {
throw new SyntaxError(errorSnippet(`JSON value expected`))
}
}
function errorSnippet(message = `Unexpected character '${lastChar}'`) {
if (!lastChar) {
message = 'Unexpected end of input'
}
const lines = buffer.slice(-40).split('\n')
const lastLine = lines.pop()
const source =
lines.map(line => ` ${line}\n`).join('')
+ ` ${lastLine}${readEOL()}\n`
const p = ` ${'.'.repeat(Math.max(0, lastLine.length - 1))}^\n`
return `${message} on line ${lineNumber}.\n\n${source}${p}`
}
function readEOL() {
let line = ''
for (const ch of stdin) {
if (!ch || ch === '\n' || line.length >= 60) break
line += ch
}
return line
}
}
function stringify(value, isPretty = false) {
const colors = {
key: isPretty ? '\x1b[1;34m' : '',
string: isPretty ? '\x1b[32m' : '',
number: isPretty ? '\x1b[36m' : '',
boolean: isPretty ? '\x1b[35m' : '',
null: isPretty ? '\x1b[2m' : '',
reset: isPretty ? '\x1b[0m' : '',
}
function getIndent(level) {
return ' '.repeat(2 * level)
}
function stringifyValue(value, level = 0) {
if (typeof value === 'string') {
return `${colors.string}"${value}"${colors.reset}`
} else if (typeof value === 'number') {
return `${colors.number}${value}${colors.reset}`
} else if (typeof value === 'bigint') {
return `${colors.number}${value}${colors.reset}`
} else if (typeof value === 'boolean') {
return `${colors.boolean}${value}${colors.reset}`
} else if (value === null || typeof value === 'undefined') {
return `${colors.null}null${colors.reset}`
} else if (Array.isArray(value)) {
if (value.length === 0) {
return `[]`
}
const items = value
.map((v) => `${getIndent(level + 1)}${stringifyValue(v, level + 1)}`)
.join(',\n')
return `[\n${items}\n${getIndent(level)}]`
} else if (typeof value === 'object') {
const keys = Object.keys(value)
if (keys.length === 0) {
return `{}`
}
const entries = keys
.map(
(key) =>
`${getIndent(level + 1)}${colors.key}"${key}"${colors.reset}: ${stringifyValue(
value[key],
level + 1
)}`
)
.join(',\n')
return `{\n${entries}\n${getIndent(level)}}`
}
throw new Error(`Unsupported value type: ${typeof value}`)
}
return stringifyValue(value)
}
function printUsage() {
const usage = `Usage
fx [flags] [code...]
Flags
-h, --help Display this help message
-r, --raw Treat input as a raw string
-s, --slurp Read all inputs into an array`
console.log(usage)
}