gistfile1.js

function all() {
    var doc = app.activeDocument;
    var itemsToLoop = [doc.layers, doc.symbolItems];

    var arrayItems = [];
    for( i = 0; i < itemsToLoop.length; i++) {
        var itemName[i] = itemsToLoop[i].name;
        arrayItems.push(itemName[i]);
    }
    
    this.numberOfItems = itemCollect;
}

all.prototype.findAndReplace = function(this.arrayItems) {
    var findTextInSymbolName = prompt("Text to find", "");
    var replaceTextInSymbolName = prompt("Text to replace", "");
    for( i = 0; i < app.activeDocument.symbolItems; i++){
        var currentSymbolName = app.activeDocument.symbolItems[i].symbol.name;
        if (currentSymbolName == findTextInSymbolName) {
            return currentObjectName = replaceTextInSymbolName;
        }
     }
}