69 lines
2.4 KiB
JavaScript
69 lines
2.4 KiB
JavaScript
'use strict'
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// hoisted due to circular dependency on command.
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module.exports = argsert
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const command = require('./command')()
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const YError = require('./yerror')
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const positionName = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth']
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function argsert (expected, callerArguments, length) {
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// TODO: should this eventually raise an exception.
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try {
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// preface the argument description with "cmd", so
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// that we can run it through yargs' command parser.
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let position = 0
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let parsed = { demanded: [], optional: [] }
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if (typeof expected === 'object') {
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length = callerArguments
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callerArguments = expected
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} else {
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parsed = command.parseCommand(`cmd ${expected}`)
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}
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const args = [].slice.call(callerArguments)
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while (args.length && args[args.length - 1] === undefined) args.pop()
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length = length || args.length
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if (length < parsed.demanded.length) {
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throw new YError(`Not enough arguments provided. Expected ${parsed.demanded.length} but received ${args.length}.`)
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}
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const totalCommands = parsed.demanded.length + parsed.optional.length
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if (length > totalCommands) {
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throw new YError(`Too many arguments provided. Expected max ${totalCommands} but received ${length}.`)
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}
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parsed.demanded.forEach((demanded) => {
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const arg = args.shift()
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const observedType = guessType(arg)
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const matchingTypes = demanded.cmd.filter(type => type === observedType || type === '*')
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if (matchingTypes.length === 0) argumentTypeError(observedType, demanded.cmd, position, false)
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position += 1
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})
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parsed.optional.forEach((optional) => {
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if (args.length === 0) return
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const arg = args.shift()
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const observedType = guessType(arg)
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const matchingTypes = optional.cmd.filter(type => type === observedType || type === '*')
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if (matchingTypes.length === 0) argumentTypeError(observedType, optional.cmd, position, true)
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position += 1
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})
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} catch (err) {
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console.warn(err.stack)
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}
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}
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function guessType (arg) {
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if (Array.isArray(arg)) {
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return 'array'
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} else if (arg === null) {
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return 'null'
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}
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return typeof arg
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}
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function argumentTypeError (observedType, allowedTypes, position, optional) {
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throw new YError(`Invalid ${positionName[position] || 'manyith'} argument. Expected ${allowedTypes.join(' or ')} but received ${observedType}.`)
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}
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