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198 lines
4.6 KiB

4 years ago
'use strict'
class FiggyPudding {
constructor (specs, opts, providers) {
this.__specs = specs || {}
Object.keys(this.__specs).forEach(alias => {
if (typeof this.__specs[alias] === 'string') {
const key = this.__specs[alias]
const realSpec = this.__specs[key]
if (realSpec) {
const aliasArr = realSpec.aliases || []
aliasArr.push(alias, key)
realSpec.aliases = [...(new Set(aliasArr))]
this.__specs[alias] = realSpec
} else {
throw new Error(`Alias refers to invalid key: ${key} -> ${alias}`)
}
}
})
this.__opts = opts || {}
this.__providers = reverse((providers).filter(
x => x != null && typeof x === 'object'
))
this.__isFiggyPudding = true
}
get (key) {
return pudGet(this, key, true)
}
get [Symbol.toStringTag] () { return 'FiggyPudding' }
forEach (fn, thisArg = this) {
for (let [key, value] of this.entries()) {
fn.call(thisArg, value, key, this)
}
}
toJSON () {
const obj = {}
this.forEach((val, key) => {
obj[key] = val
})
return obj
}
* entries (_matcher) {
for (let key of Object.keys(this.__specs)) {
yield [key, this.get(key)]
}
const matcher = _matcher || this.__opts.other
if (matcher) {
const seen = new Set()
for (let p of this.__providers) {
const iter = p.entries ? p.entries(matcher) : entries(p)
for (let [key, val] of iter) {
if (matcher(key) && !seen.has(key)) {
seen.add(key)
yield [key, val]
}
}
}
}
}
* [Symbol.iterator] () {
for (let [key, value] of this.entries()) {
yield [key, value]
}
}
* keys () {
for (let [key] of this.entries()) {
yield key
}
}
* values () {
for (let [, value] of this.entries()) {
yield value
}
}
concat (...moreConfig) {
return new Proxy(new FiggyPudding(
this.__specs,
this.__opts,
reverse(this.__providers).concat(moreConfig)
), proxyHandler)
}
}
try {
const util = require('util')
FiggyPudding.prototype[util.inspect.custom] = function (depth, opts) {
return (
this[Symbol.toStringTag] + ' '
) + util.inspect(this.toJSON(), opts)
}
} catch (e) {}
function BadKeyError (key) {
throw Object.assign(new Error(
`invalid config key requested: ${key}`
), {code: 'EBADKEY'})
}
function pudGet (pud, key, validate) {
let spec = pud.__specs[key]
if (validate && !spec && (!pud.__opts.other || !pud.__opts.other(key))) {
BadKeyError(key)
} else {
if (!spec) { spec = {} }
let ret
for (let p of pud.__providers) {
ret = tryGet(key, p)
if (ret === undefined && spec.aliases && spec.aliases.length) {
for (let alias of spec.aliases) {
if (alias === key) { continue }
ret = tryGet(alias, p)
if (ret !== undefined) {
break
}
}
}
if (ret !== undefined) {
break
}
}
if (ret === undefined && spec.default !== undefined) {
if (typeof spec.default === 'function') {
return spec.default(pud)
} else {
return spec.default
}
} else {
return ret
}
}
}
function tryGet (key, p) {
let ret
if (p.__isFiggyPudding) {
ret = pudGet(p, key, false)
} else if (typeof p.get === 'function') {
ret = p.get(key)
} else {
ret = p[key]
}
return ret
}
const proxyHandler = {
has (obj, prop) {
return prop in obj.__specs && pudGet(obj, prop, false) !== undefined
},
ownKeys (obj) {
return Object.keys(obj.__specs)
},
get (obj, prop) {
if (
typeof prop === 'symbol' ||
prop.slice(0, 2) === '__' ||
prop in FiggyPudding.prototype
) {
return obj[prop]
}
return obj.get(prop)
},
set (obj, prop, value) {
if (
typeof prop === 'symbol' ||
prop.slice(0, 2) === '__'
) {
obj[prop] = value
return true
} else {
throw new Error('figgyPudding options cannot be modified. Use .concat() instead.')
}
},
deleteProperty () {
throw new Error('figgyPudding options cannot be deleted. Use .concat() and shadow them instead.')
}
}
module.exports = figgyPudding
function figgyPudding (specs, opts) {
function factory (...providers) {
return new Proxy(new FiggyPudding(
specs,
opts,
providers
), proxyHandler)
}
return factory
}
function reverse (arr) {
const ret = []
arr.forEach(x => ret.unshift(x))
return ret
}
function entries (obj) {
return Object.keys(obj).map(k => [k, obj[k]])
}