The replacefirst helper replaces only the first occurrence of a specified substring with another value, leaving all later occurrences unchanged. Use it to substitute a known prefix or leading marker without modifying the rest of the string.
Syntax
{{replacefirst str a b}}
str -- The input string. Required.
a -- The substring to replace. Required. Matching is case-sensitive.
b -- The replacement value. Required. Pass "" to delete the first occurrence.
Examples
Replace the first occurrence of a character
{{replacefirst record.text "a" "z"}}
Input:
{ "record": { "text": "a b a b a b" } }
Output: z b a b a b
The first "a" is replaced with "z". The remaining two instances are unchanged.
Replace the first occurrence of a word
{{replacefirst record.note "Order" "Invoice"}}
Input:
{ "record": { "note": "Order Order Order" } }
Output: Invoice Order Order
Only the first "Order" is replaced. The other two remain.
Usage notes
- Only the first match is replaced. All subsequent occurrences remain unchanged.
- Matching is case-sensitive:
"Order"and"order"are treated as different substrings. - Pass
""as the replacement to delete only the first occurrence. To remove all occurrences, use{{regexReplace field "" "substring" "g"}}instead. - To replace all occurrences, use the replace helper instead.