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A very minimal Javascript (ES5 & ES6) Middleware Pattern Implementation
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class Middleware { | |
constructor() { | |
// Array prototype last | |
if (!Array.prototype.last) { | |
Array.prototype.last = function() { | |
return this[this.length - 1]; | |
} | |
} | |
// Array prototype reduceOneRight | |
if (!Array.prototype.reduceOneRight) { | |
Array.prototype.reduceOneRight = function() { | |
return this.slice(0, -1); | |
} | |
} | |
} | |
use(fn) { | |
this.go = ((stack) => (...args) => stack(...args.reduceOneRight(), () => { | |
let _next = args.last(); | |
fn.apply(this, [...args.reduceOneRight(), _next.bind.apply(_next, [null, ...args.reduceOneRight()])]); | |
}))(this.go); | |
} | |
go(...args) { | |
let _next = args.last(); | |
_next.apply(this, args.reduceOneRight()); | |
} | |
} |
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var middleware = new Middleware(); | |
middleware.use((hook, next) => { | |
setTimeout(() => { | |
hook.value++; | |
next(); | |
}, 10); | |
}); | |
middleware.use((hook, next) => { | |
setTimeout(() => { | |
hook.value++; | |
next(); | |
}, 10); | |
}); | |
var start = new Date(); | |
middleware.go({value:1}, (hook) => { | |
console.log(hook.value); // 3 | |
console.log(new Date() - start); // around 20 | |
}); |
In order to chain a lá
middleware
.use(fn)
.use(fn)
you could return this
at the end of the use
method.
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Modifying the array prototype seems unnecessary, with potential consequences. This version accomplishes the same thing.