3 files changed, 36 insertions, 0 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dfeb517..bbfecf8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 - The `iterator` module gains the `index`, `iterate`, `zip`, `scan`,
   `take_while`, `drop_while`, `chunk`, `sized_chunk`, `intersperse`, `any` and `all` functions.
 - Breaking change in `iterator.take`. Now it returns an iterator instead of a list.
+- The `string` module gains the `drop_before` function.
 
 ## v0.14.0 - 2021-02-18
 
diff --git a/src/gleam/string.gleam b/src/gleam/string.gleam
index 7f7653c..1bec6a5 100644
--- a/src/gleam/string.gleam
+++ b/src/gleam/string.gleam
@@ -167,6 +167,20 @@ pub fn slice(from string: String, at_index idx: Int, length len: Int) -> String
   }
 }
 
+/// Drops contents of the first string that occur before the second string.
+/// If the first string does not contain the second string, the first string is returned.
+///
+/// ## Examples
+///    > drop_before(from: "The Lone Gunmen", before: "Lone")
+///    "Lone Gunmen"
+///
+pub fn drop_before(from string: String, before substring: String) -> String {
+  case split_once(string, substring) {
+    Ok(tuple(_, rest)) -> concat([substring, rest])
+    Error(Nil) -> string
+  }
+}
+
 /// Drops *n* Graphemes from the left side of a string.
 ///
 /// ## Examples
diff --git a/test/gleam/string_test.gleam b/test/gleam/string_test.gleam
index 2d563b4..b0e0fe6 100644
--- a/test/gleam/string_test.gleam
+++ b/test/gleam/string_test.gleam
@@ -204,6 +204,27 @@ pub fn slice_test() {
   |> should.equal("")
 }
 
+pub fn drop_before_test() {
+  "gleam"
+  |> string.drop_before("gl")
+  |> should.equal("gleam")
+
+  "gleam"
+  |> string.drop_before("le")
+  |> should.equal("leam")
+
+  string.drop_before(from: "gleam", before: "ea")
+  |> should.equal("eam")
+
+  "gleam"
+  |> string.drop_before("")
+  |> should.equal("gleam")
+
+  "gleam"
+  |> string.drop_before("!")
+  |> should.equal("gleam")
+}
+
 pub fn drop_left_test() {
   "gleam"
   |> string.drop_left(up_to: 2)