Parsing JSON in Office Scripts - not iterable - json

Question

I am attempting to parse JSON in Office Scripts that prints the headings and row information on the sheet. I'm successfully fetching the data, but I keep getting the error message that my information is not iterable on the "for" line.
async function main(workbook: ExcelScript.Workbook) {
// Call the API
const response = await fetch('WEBADDRESSHERE');
const sitedata: siteInformation[] = await response.json();
// Set the types for rows
const rows: (string | number)[][]=[];
// Iterate through the data and get the row headings
for (let site of sitedata){
rows.push([site.SiteID, site.SiteDescription, site.EffectiveDate, site.DataPresent]);
}
// Get the current sheet
const sheet = workbook.getActiveWorksheet();
// Set the range to start writing the details
const range = sheet.getRange('A2').getResizedRange(rows.length - 1, rows[0].length - 1);
range.setValues(rows);
return;
}
interface siteInformation {
SiteID: string;
SiteDescription: string;
EffectiveDate: date;
DataPresent: string;
}
This is the sample JSON I'm working with.
{
"1": {
"SiteID": "2",
"SiteDescription": "SiteA",
"EffectiveDate": "2022-08-01",
"DataPresent": "Yes"
},
"2": {
"SiteID": "2",
"SiteDescription": "SiteA",
"EffectiveDate": "2022-08-02",
"DataPresent": "Yes"
}
}

Answer 1

There are a few things going on here
I believe the reason you're getting the "not iterable" error is because you're using the wrong loop. To loop through a JSON dictionary, you need to use for...in... not for...of...
Second, when you update the loop, you'll get the key back as the element. So you need to use the key with the sitedata to get the specific JSON element you're trying to loop through.
Lastly, although it's not necessary, you listed the date type as a type in the interface. This is showing an error on the office scripts IDE for me. So you may want to update that to string.
You can see a code snippet with the updates below:
async function main(workbook: ExcelScript.Workbook) {
// Call the API
const sitedataStr = `{
"1": {
"SiteID": "1",
"SiteDescription": "SiteA",
"EffectiveDate": "2022-08-01",
"DataPresent": "Yes"
},
"2": {
"SiteID": "2",
"SiteDescription": "SiteA",
"EffectiveDate": "2022-08-02",
"DataPresent": "Yes"
}
}`
let sitedata: siteInformation = JSON.parse(sitedataStr)
// Set the types for rows
const rows: (string | number)[][] = [];
// Iterate through the data and get the row headings
for (let key in sitedata) {
let site:siteInformation = sitedata[key]
rows.push([site.SiteID, site.SiteDescription, site.EffectiveDate, site.DataPresent]);
}
}
interface siteInformation {
SiteID: string;
SiteDescription: string;
EffectiveDate: string;
DataPresent: string;
}