abbrev.js
1.72 KB
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module.exports = exports = abbrev.abbrev = abbrev
abbrev.monkeyPatch = monkeyPatch
function monkeyPatch () {
Object.defineProperty(Array.prototype, 'abbrev', {
value: function () { return abbrev(this) },
enumerable: false, configurable: true, writable: true
})
Object.defineProperty(Object.prototype, 'abbrev', {
value: function () { return abbrev(Object.keys(this)) },
enumerable: false, configurable: true, writable: true
})
}
function abbrev (list) {
if (arguments.length !== 1 || !Array.isArray(list)) {
list = Array.prototype.slice.call(arguments, 0)
}
for (var i = 0, l = list.length, args = [] ; i < l ; i ++) {
args[i] = typeof list[i] === "string" ? list[i] : String(list[i])
}
// sort them lexicographically, so that they're next to their nearest kin
args = args.sort(lexSort)
// walk through each, seeing how much it has in common with the next and previous
var abbrevs = {}
, prev = ""
for (var i = 0, l = args.length ; i < l ; i ++) {
var current = args[i]
, next = args[i + 1] || ""
, nextMatches = true
, prevMatches = true
if (current === next) continue
for (var j = 0, cl = current.length ; j < cl ; j ++) {
var curChar = current.charAt(j)
nextMatches = nextMatches && curChar === next.charAt(j)
prevMatches = prevMatches && curChar === prev.charAt(j)
if (!nextMatches && !prevMatches) {
j ++
break
}
}
prev = current
if (j === cl) {
abbrevs[current] = current
continue
}
for (var a = current.substr(0, j) ; j <= cl ; j ++) {
abbrevs[a] = current
a += current.charAt(j)
}
}
return abbrevs
}
function lexSort (a, b) {
return a === b ? 0 : a > b ? 1 : -1
}