Add trimstr/1 function (#3319)

docs/content/manual/dev/manual.yml

@@ -1798,6 +1798,17 @@ sections:
             input: '["fo", "foo", "barfoo", "foobar", "foob"]'
             output: ['["fo","","bar","foobar","foob"]']
 
+      - title: "`trimstr(str)`"
+        body: |
+
+          Outputs its input with the given string removed at both ends, if it
+          starts or ends with it.
+
+        examples:
+          - program: '[.[]|trimstr("foo")]'
+            input: '["fo", "foo", "barfoo", "foobarfoo", "foob"]'
+            output: ['["fo","","bar","bar","b"]']
+
       - title: "`trim`, `ltrim`, `rtrim`"
         body: |
 

jq.1.prebuilt

@@ -1959,6 +1959,21 @@ jq \'[\.[]|rtrimstr("foo")]\'
 .
 .IP "" 0
 .
+.SS "trimstr(str)"
+Outputs its input with the given string removed at both ends, if it starts or ends with it\.
+.
+.IP "" 4
+.
+.nf
+
+jq \'[\.[]|trimstr("foo")]\'
+   ["fo", "foo", "barfoo", "foobarfoo", "foob"]
+=> ["fo","","bar","bar","b"]
+.
+.fi
+.
+.IP "" 0
+.
 .SS "trim, ltrim, rtrim"
 \fBtrim\fR trims both leading and trailing whitespace\.
 .

src/builtin.jq

@@ -76,6 +76,7 @@ def fromdate: fromdateiso8601;
 def todate: todateiso8601;
 def ltrimstr($left): if startswith($left) then .[$left | length:] end;
 def rtrimstr($right): if endswith($right) then .[:$right | -length] end;
+def trimstr($val): ltrimstr($val) | rtrimstr($val);
 def match(re; mode): _match_impl(re; mode; false)|.[];
 def match($val): ($val|type) as $vt | if $vt == "string" then match($val; null)
    elif $vt == "array" and ($val | length) > 1 then match($val[0]; $val[1])

tests/jq.test

@@ -1508,6 +1508,10 @@ split("")
 ["fo", "foo", "barfoo", "foobar", "foob"]
 ["fo","","bar","foobar","foob"]
 
+[.[]|trimstr("foo")]
+["fo", "foo", "barfoo", "foobarfoo", "foob"]
+["fo","","bar","bar","b"]
+
 [(index(","), rindex(",")), indices(",")]
 "a,bc,def,ghij,klmno"
 [1,13,[1,4,8,13]]

tests/man.test

@@ -617,6 +617,10 @@ combinations(2)
 ["fo", "foo", "barfoo", "foobar", "foob"]
 ["fo","","bar","foobar","foob"]
 
+[.[]|trimstr("foo")]
+["fo", "foo", "barfoo", "foobarfoo", "foob"]
+["fo","","bar","bar","b"]
+
 trim, ltrim, rtrim
 " abc "
 "abc"