in src/connectors/sheets-connector.js [264:271]
getPropertyIndex(tabId, lookupKey) {
let propertyLookup = this.getPropertyLookup(tabId);
for (let i = 0; i < propertyLookup.length; i++) {
if (propertyLookup[i] === lookupKey) {
return i + 1;
}
}
}