lib.strings.concatMapAttrsStringSep: init

1 files changed, 37 insertions, 0 deletions

diff --git a/lib/strings.nix b/lib/strings.nix
index d9a2d786ed28..5ea86e0d7e07 100644
--- a/lib/strings.nix
+++ b/lib/strings.nix
@@ -270,6 +270,43 @@ rec {
     list: concatStringsSep sep (lib.imap1 f list);
 
   /**
+    Like [`concatMapStringsSep`](#function-library-lib.strings.concatMapStringsSep)
+    but takes an attribute set instead of a list.
+
+    # Inputs
+
+    `sep`
+    : Separator to add between item strings
+
+    `f`
+    : Function that takes each key and value and return a string
+
+    `attrs`
+    : Attribute set to map from
+
+    # Type
+
+    ```
+    concatMapAttrsStringSep :: String -> (String -> Any -> String) -> AttrSet -> String
+    ```
+
+    # Examples
+
+    :::{.example}
+    ## `lib.strings.concatMapAttrsStringSep` usage example
+
+    ```nix
+    concatMapAttrsStringSep "\n" (name: value: "${name}: foo-${value}") { a = "0.1.0"; b = "0.2.0"; }
+    => "a: foo-0.1.0\nb: foo-0.2.0"
+    ```
+
+    :::
+  */
+  concatMapAttrsStringSep =
+    sep: f: attrs:
+    concatStringsSep sep (lib.attrValues (lib.mapAttrs f attrs));
+
+  /**
     Concatenate a list of strings, adding a newline at the end of each one.
     Defined as `concatMapStrings (s: s + "\n")`.