lib/classes/Variables.js/Variables/populateProperty
class Variables:  populateProperty(propertyParam) {
    let property = propertyParam;
    let valueToPopulate;
    if (typeof property === 'string' && property.match(this.variableSyntax)) {
      property.match(this.variableSyntax).forEach((matchedString) => {
        const variableString = matchedString
          .replace(this.variableSyntax, (match, varName) => varName.trim())
          .replace(/\s/g, '');

        if (variableString.match(this.overwriteSyntax)) {
          valueToPopulate = this.overwrite(variableString);
        } else {
          valueToPopulate = this.getValueFromSource(variableString);
        }

        property = this.populateVariable(property, matchedString, valueToPopulate);
      });
      return this.populateProperty(property);
    }
    return property;
  }