61 lines
2.3 KiB
JavaScript
61 lines
2.3 KiB
JavaScript
|
/***
|
||
|
|
Copyright 2013 Teun Duynstee
|
||
|
|
|
||
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
you may not use this file except in compliance with the License.
|
||
|
|
You may obtain a copy of the License at
|
||
|
|
|
||
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
|
||
|
|
Unless required by applicable law or agreed to in writing, software
|
||
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
See the License for the specific language governing permissions and
|
||
|
|
limitations under the License.
|
||
|
|
*/
|
||
|
|
module.exports = (function() {
|
||
|
|
|
||
|
|
function identity(v){return v;}
|
||
|
|
|
||
|
|
function ignoreCase(v){return typeof(v)==="string" ? v.toLowerCase() : v;}
|
||
|
|
|
||
|
|
function makeCompareFunction(f, opt){
|
||
|
|
opt = typeof(opt)==="object" ? opt : {direction:opt};
|
||
|
|
|
||
|
|
if(typeof(f)!="function"){
|
||
|
|
var prop = f;
|
||
|
|
// make unary function
|
||
|
|
f = function(v1){return !!v1[prop] ? v1[prop] : "";}
|
||
|
|
}
|
||
|
|
if(f.length === 1) {
|
||
|
|
// f is a unary function mapping a single item to its sort score
|
||
|
|
var uf = f;
|
||
|
|
var preprocess = opt.ignoreCase?ignoreCase:identity;
|
||
|
|
var cmp = opt.cmp || function(v1,v2) {return v1 < v2 ? -1 : v1 > v2 ? 1 : 0;}
|
||
|
|
f = function(v1,v2) {return cmp(preprocess(uf(v1)), preprocess(uf(v2)));}
|
||
|
|
}
|
||
|
|
const descTokens = {"-1":'', desc:''};
|
||
|
|
if(opt.direction in descTokens) return function(v1,v2){return -f(v1,v2)};
|
||
|
|
return f;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* adds a secondary compare function to the target function (`this` context)
|
||
|
|
which is applied in case the first one returns 0 (equal)
|
||
|
|
returns a new compare function, which has a `thenBy` method as well */
|
||
|
|
function tb(func, opt) {
|
||
|
|
/* should get value false for the first call. This can be done by calling the
|
||
|
|
exported function, or the firstBy property on it (for es6 module compatibility)
|
||
|
|
*/
|
||
|
|
var x = (typeof(this) == "function" && !this.firstBy) ? this : false;
|
||
|
|
var y = makeCompareFunction(func, opt);
|
||
|
|
var f = x ? function(a, b) {
|
||
|
|
return x(a,b) || y(a,b);
|
||
|
|
}
|
||
|
|
: y;
|
||
|
|
f.thenBy = tb;
|
||
|
|
return f;
|
||
|
|
}
|
||
|
|
tb.firstBy = tb;
|
||
|
|
return tb;
|
||
|
|
})();
|