findreplace.js

(function() {
    function parseMoney(grp) {
        return parseFloat(grp[1].replace(/,/g, ''));
    }

    function roundToPlaces(num, places) {
        var scale = Math.pow(10, places);
        return Math.round(num * scale) / scale;
    }

    function randFromArray(arr) {
        return arr[Math.floor(Math.random() * arr.length)];
    }

    var xhr = new XMLHttpRequest();
    //http://stackoverflow.com/questions/354044/what-is-the-best-u-s-currency-regex
    var re = /\$[+-]?([0-9,]+(?:\.[0-9]+)?)( (million|billion|trillion|thousand))?/i;
    var elements = document.getElementsByTagName('*');
    
    chrome.storage.sync.get(['currencyType'], function(storage) {
        xhr.onreadystatechange = function() {
            if (xhr.readyState != XMLHttpRequest.DONE) {
                return;
            }

            var items = JSON.parse(xhr.responseText);

            // XXX: can't we just regex on the whole HTML (i.e. body text contents)?
            for (var j = 0; j < elements.length; j++) {
                var elt = elements[j];
                for (var k = 0; k < elt.childNodes.length; k++) {
                    var child = elt.childNodes[k];
                    if (child.nodeType === 3) {
                        var txt = child.nodeValue;
                        // find/replace until there are none left
                        var match;
                        while (match = txt.match(re)) {
                            var item = randFromArray(items);

                            if (storage.currencyType == 'classic') {
                                item = items[0];
                            }

                            var itemAmt = parseMoney(match) / item.price;
                            if (itemAmt < 0.01) {
                                itemAmt = 0.01;
                            }
                            itemAmt = roundToPlaces(itemAmt, 2);
                            var written = match[2] ? match[2].trim() : "";
                            var itemName = item.name;
                            // contextual capitalization only if millions/billions was matched
                            if (written !== "" && written[0] === written[0].toUpperCase()) {
                                itemName = itemName.split(' ').map(function(elt) {
                                    return elt == "of" ? elt : elt[0].toUpperCase() + elt.substring(1);
                                }).join(' ');
                            }
                            txt = txt.replace(re, itemAmt + (written ? " " + written : "") + " " + itemName);
                        }
                        elt.replaceChild(document.createTextNode(txt), child);
                    }
                }
            }
        }; // Implemented elsewhere.
    });
    xhr.open("GET", chrome.extension.getURL('/things.json'), true);
    xhr.send();
})();