ERROR TypeError: Cannot read property 'replace' of null

Question

I am getting a TypeError, although my application is running properly.

"ERROR TypeError: Cannot read property 'replace' of null"

Don't get how to resolve this. Could any one give me some idea or help me to understand why this is happening?

if (isInitial) {
    // Add Data Rows (initially)
    for (const row of rows) {
        const clientVisitGuid = row[2];
        const location = row[3];
        row[5] = row[5].replace(/\//g, '\/\u200B');
        const service = row[5];
        const rowId = `${service || 'zzz'}_${location}_${clientVisitGuid}`;
        const sortString = `${service || 'zzz'}_${location}_${clientVisitGuid}`;
        const daysPastDischarge = parseInt(row[6]);
        const isMarked = parseInt(row[7]) === 1 ? true : false;
        if (cbt.hasBodyRow(rowId) === false) {
            const values: Array<[string, string | number]> = [];
            let isAllClear = true;
            for (let i = 0; i < row.length; i++) {
                const colId: string = cbt.headerRow.headerCols[i].id;
                const colVal: string | number = row[i];
                if (cbt.headerRow.headerCols[i].isFlag === true && colVal !== 1) {
                    isAllClear = false;
                }
                values.push([colId, colVal]);
            }
            const valueHash = hash(JSON.stringify(row));
            cbt.addBodyRow(
                rowId,
                values,
                valueHash,
                sortString,
                daysPastDischarge,
                isMarked,
                isAllClear,
                true,
            );
        }
    }
}

Answer 1

To fix error you need to check if variable exists before trying to replace the string. Wrap it with an if statement like this:

if(row[5]) {
    row[5] = row[5].replace(/\//g, '\/\u200B');
    const service = row[5];
}

Answer 2

Looks like the row[5] is null. You should first check if the row[5] exists. Something like

if(row[5]) {
     row[5] = row[5].replace(/\//g, '\/\u200B');
     const service = row[5];
} 

You should also consider adding some handling event when the value is empty