What is this? Essentially I needed a way of serializing js statements to pass to phantom js, meaning the functions can not depend on the ability to refer to any outside variables.
Consider (assuming you have a phantom js page object):
x = 6
y = 7
selector = ".div"
page.evaluate -> $(selector).addClass("#div-#{x}-#{y}")This will fail as it refers to selector, x, and y.
Chain allows you to build a function returning a call chain:
COS = require "chain-of-strength"
x = 6
y = 7
selector = ".div"
page.evaluate COS.func $: selector, addClass: "#div-#{x}-#{y}"
Obviously this is a little more noisy, but definitely nicer than
page.evaluate "function(){ return $('#{selector}').addClass('#div-#{x}-#{y}') }"You can also just get a raw method chain w/o a function wrapper by calling buildChain
COS.buildChain ['a', b: [1,2]]
#yields
"a.b(1,2)"There are times when you may want to have a nested callback e.g. to a map/filter method
COS.func $: selector, map: func: ["$(this)", css: "display"]
#yields
'function(){return $(".div").map(function(){return $(this).css("display")})}'