getPrototypesFromFunctionNames(functionList) {
    const ret = [];
    for (let i = 0; i < functionList.length; ++i) {
      const functionName = functionList[i];
      const functionIndex = this.nativeFunctionNames.indexOf(functionName);
      if (functionIndex > -1) {
        ret.push(this.nativeFunctions[functionIndex].source);
        continue;
      }
      const node = this.functionMap[functionName];
      if (node) {
        ret.push(node.toString());
      }
    }
    return ret;
  }
@desc Return string of all functions converted
@param {String[]} functionList - List of function names to build the string.
@returns {Array} Prototypes of all functions converted