Created
December 7, 2015 15:17
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Javascript browser sortBy function
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(function(){ | |
function get(k) { | |
return function(o) { | |
return o[k] | |
} | |
} | |
function maybeWrap(callback) { | |
// substitute a string to a callback to define a property getter | |
return (typeof callback === 'string') ? get(callback) : callback | |
} | |
function reverse(callback) { | |
callback.__sortDesc = true | |
return callback | |
} | |
function sortBy() { | |
var funs = Array.prototype.slice.call(arguments).map(maybeWrap) | |
var sorter = function(objA, objB) { | |
// console.log('iter -----------') | |
var i = 0, f | |
while(funs[i]) { | |
f = funs[i] | |
// console.log('using fun ', i) | |
var a, b | |
if (f.__sortDesc) { | |
b = f(objA) | |
a = f(objB) | |
} else { | |
a = f(objA) | |
b = f(objB) | |
} | |
// console.log('comparing ', a, b) | |
// if (a < b) console.log('result ', -1, objA, objB) | |
// if (a > b) console.log('result ', 1, objA, objB) | |
if (a < b) return -1 | |
if (a > b) return 1 | |
// try another callback | |
// console.log('equals') | |
i += 1 | |
} | |
return 0 | |
} | |
sorter.desc = function(callback) { | |
funs.push(reverse(maybeWrap(callback))) | |
return sorter | |
} | |
sorter.asc = function(callback) { | |
funs.push(maybeWrap(callback)) | |
return sorter | |
} | |
return sorter | |
} | |
// var test = [ | |
// {x:2.5,key:3000,name:'dddd'}, | |
// {x:2.5,key:4000,name:'cccc'}, | |
// {x:3.5,key:2000,name:'bbbb'}, | |
// {x:3.5,key:1000,name:'aaaa'} | |
// ] | |
// function dump(it) { | |
// return [it.key,it.name,'x='+it.x].join(':') | |
// } | |
// function ftest (code, expect) { | |
// // console.log('-------------------------------------') | |
// // console.log('test ' + code) | |
// var sorted = eval(code) | |
// // console.log(sorted.map(dump)) | |
// var f1000 = x => x / 1000 | |
// var result = sorted.map(get('key')).map(f1000).join('') | |
// if (result !== expect) { | |
// console.log('FAIL') | |
// console.log('expected ', expect) | |
// console.log('result ', result) | |
// } | |
// } | |
// ftest("test.sort(sortBy('key'))", '1234') | |
// ftest("test.sort(sortBy().asc('key'))", '1234') | |
// ftest("test.sort(sortBy().desc('x').desc('name'))", '2134') | |
// ftest("test.sort(sortBy().desc('x').asc('name'))", '1243') | |
// ftest("test.sort(sortBy('x').asc('name'))", '4312') | |
// ftest("test.sort(sortBy('x').desc('name'))", '3421') | |
// ftest("test.sort(sortBy('name').desc('x'))", '1243') | |
window.sortBy = sortBy | |
}()) |
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