index.js
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/*
* Module dependencies
*/
var balanced = require("balanced-match")
/**
* Expose `reduceFunctionCall`
*
* @type {Function}
*/
module.exports = reduceFunctionCall
/**
* Walkthrough all expressions, evaluate them and insert them into the declaration
*
* @param {Array} expressions
* @param {Object} declaration
*/
function reduceFunctionCall(string, functionRE, callback) {
var call = string
return getFunctionCalls(string, functionRE).reduce(function(string, obj) {
return string.replace(obj.functionIdentifier + "(" + obj.matches.body + ")", evalFunctionCall(obj.matches.body, obj.functionIdentifier, callback, call, functionRE))
}, string)
}
/**
* Parses expressions in a value
*
* @param {String} value
* @returns {Array}
* @api private
*/
function getFunctionCalls(call, functionRE) {
var expressions = []
var fnRE = typeof functionRE === "string" ? new RegExp("\\b(" + functionRE + ")\\(") : functionRE
do {
var searchMatch = fnRE.exec(call)
if (!searchMatch) {
return expressions
}
if (searchMatch[1] === undefined) {
throw new Error("Missing the first couple of parenthesis to get the function identifier in " + functionRE)
}
var fn = searchMatch[1]
var startIndex = searchMatch.index
var matches = balanced("(", ")", call.substring(startIndex))
if (!matches || matches.start !== searchMatch[0].length - 1) {
throw new SyntaxError(fn + "(): missing closing ')' in the value '" + call + "'")
}
expressions.push({matches: matches, functionIdentifier: fn})
call = matches.post
}
while (fnRE.test(call))
return expressions
}
/**
* Evaluates an expression
*
* @param {String} expression
* @returns {String}
* @api private
*/
function evalFunctionCall (string, functionIdentifier, callback, call, functionRE) {
// allow recursivity
return callback(reduceFunctionCall(string, functionRE, callback), functionIdentifier, call)
}