helpers.coffee | |
|---|---|
| This file contains the common helper functions that we'd like to share among the Lexer, Rewriter, and the Nodes. Merge objects, flatten arrays, count characters, that sort of thing. | |
| Peek at the beginning of a given string to see if it matches a sequence. | exports.starts = (string, literal, start) ->
literal is string.substr start, literal.length |
| Peek at the end of a given string to see if it matches a sequence. | exports.ends = (string, literal, back) ->
len = literal.length
literal is string.substr string.length - len - (back or 0), len |
| Trim out all falsy values from an array. | exports.compact = (array) ->
item for item in array when item |
| Count the number of occurrences of a string in a string. | exports.count = (string, substr) ->
num = pos = 0
return 1/0 unless substr.length
num++ while pos = 1 + string.indexOf substr, pos
num |
| Merge objects, returning a fresh copy with attributes from both sides.
Used every time | exports.merge = (options, overrides) ->
extend (extend {}, options), overrides |
| Extend a source object with the properties of another object (shallow copy). | extend = exports.extend = (object, properties) ->
for key, val of properties
object[key] = val
object |
| Return a flattened version of an array.
Handy for getting a list of | exports.flatten = flatten = (array) ->
flattened = []
for element in array
if element instanceof Array
flattened = flattened.concat flatten element
else
flattened.push element
flattened |
| Delete a key from an object, returning the value. Useful when a node is looking for a particular method in an options hash. | exports.del = (obj, key) ->
val = obj[key]
delete obj[key]
val |
| Gets the last item of an array(-like) object. | exports.last = (array, back) -> array[array.length - (back or 0) - 1]
|