diff --git a/index.ts b/index.ts
index 2219381..577ee75 100644
--- a/index.ts
+++ b/index.ts
@@ -3113,7 +3113,7 @@ const $setDifference = at('$setDifference');
 const $setEquals = pta('$setEquals');
 
 // TODO
-const $setField = (field: string, value: Expression, input: ObjectExpression) => ({
+const $setField = (input: ObjectExpression, field: string, value: Expression) => ({
   $setField: { field, input, value },
 });
 
diff --git a/pipeline.test.ts b/pipeline.test.ts
index 3638cb2..0cb6f30 100644
--- a/pipeline.test.ts
+++ b/pipeline.test.ts
@@ -1571,7 +1571,7 @@ describe('aggregation', () => {
         expect($.setField).toStrictEqual($.$setField);
       });
       it('returns expected result', () => {
-        expect($.setField('foo', '$value', '$doc')).toEqual({
+        expect($.setField('$doc', 'foo', '$value')).toEqual({
           $setField: {
             field: 'foo',
             value: '$value',