I'm looking to lower my overhead on code like this
foo(bar(baz("hello"))) // function hell
ideally something like this
var fbb = bind(foo, bar, baz)
foo("hello")
Does this exist? Native or library?
I looked through underscore and bind.
3 Answers
Underscore has the compose function which will do what you want:
var composite = _.compose(foo, bar, baz);
composite('hello');
function foo(a1){
return 'foo' + a1;
}
function bar(a2){
return 'bar' + a2;
}
function baz(a3){
return 'baz' + a3;
}
alert(foo(bar(baz("hello"))));
var composite = _.compose(foo, bar, baz);
alert( composite('hello') );<script src="//cdnjs.cloudflare.com/ajax/libs/underscore.js/1.7.0/underscore-min.js"></script>
Comments
function getCaller(first) {
var rest = Array.prototype.slice.call(arguments, 1);
return function (value) {
return rest.reduce(function (previous, next) {
return next(previous);
}, first(value));
};
}
function foo(string) {
return string + ' world!';
}
function bar(string) {
return string + ' Hi';
}
function baz(string) {
return string + ' Mom!';
}
var caller = getCaller(foo, bar, baz);
console.log(caller('Hello'));
// Prints: Hello world! Hi Mom!
answered Dec 2, 2014 at 9:36
Jackson Ray Hamilton
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2 Comments
ThomasReggi
Hey! Thanks so much for this! I was wondering if there's any way to accept multiple arguments for the last function? I know I used strings in the example above but my real-life example looks something more like
await(Promise.promisify(fs.copy(newIconPath, appIconPath))) thoughts?Jackson Ray Hamilton
Functions only return one value so that makes your requirement illogical. However, you could make a special case where, if an array is returned,
apply the array instead of passing the array as an argument to next, but that prevents you from passing an array as an argument to next, which is a very likely scenario.var bind = function() {
var fns = Array.prototype.slice.call(arguments).reverse();
return function(value) {
for (var key in fns) {
var fn = fns[key];
console.log(fn);
value = fn(value);
}
return value;
}
}
function plusTomato(value) {
return value + "tomato";
}
function plusPear(value) {
return value + "pear";
}
var plus = bind(plusTomato, plusPear);
var y = plus("pancake"); //pankaketomatopear
console.log(y);
var x = plusTomato(plusPear("pancake")); //pankaketomatopear
console.log(x);
1 Comment
Bergi
Why do you call that function
bind? It doesn't bind anything. Also, never enumerate arrays using for in
function fbb(s) { return foo(bar(baz(s))); }