Merge pull request #23 from planetscale/named-parameters

Support named parameter replacement

Author: dgraham

README.md

@@ -84,6 +84,12 @@ const results = await conn.execute('select 1 from dual where 1=?', [42])
 console.log(results)
 ```
 
+Named replacement parameters are supported with a colon prefix.
+
+```ts
+const results = await conn.execute('select 1 from dual where 1=:id', { id: 42 })
+```
+
 ## Development
 
 ```

__tests__/sanitization.test.ts

@@ -2,7 +2,24 @@ import { format } from '../src/sanitization'
 
 describe('sanitization', () => {
   describe('format', () => {
-    test('does nothing with empty values', () => {
+    test('does no replacement for missing object key', () => {
+      const query = 'select 1 from user where id=:id'
+      expect(format(query, {})).toEqual(query)
+    })
+
+    test('replaces named parameters', () => {
+      const query = 'select 1 from user where state in (:state) and deleted_at=:deleted_at'
+      const expected = "select 1 from user where state in ('active', 'inactive') and deleted_at=true"
+      expect(format(query, { state: ['active', 'inactive'], deleted_at: true })).toEqual(expected)
+    })
+
+    test('replaces duplicate named parameters', () => {
+      const query = 'select 1 from user where id=:id or actor_id=:id'
+      const expected = 'select 1 from user where id=42 or actor_id=42'
+      expect(format(query, { id: 42 })).toEqual(expected)
+    })
+
+    test('does nothing with empty values list', () => {
       const query = 'select 1 from user where id=?'
       expect(format(query, [])).toEqual(query)
     })

src/sanitization.ts

@@ -1,13 +1,24 @@
 type Stringable = { toString: () => string }
 type Value = null | undefined | number | boolean | string | Array<Value> | Date | Stringable
 
-export function format(query: string, values: Value[]): string {
+export function format(query: string, values: Value[] | Record<string, Value>): string {
+  return Array.isArray(values) ? replacePosition(query, values) : replaceNamed(query, values)
+}
+
+function replacePosition(query: string, values: Value[]): string {
   let index = 0
   return query.replace(/\?/g, (match) => {
     return index < values.length ? sanitize(values[index++]) : match
   })
 }
 
+function replaceNamed(query: string, values: Record<string, Value>): string {
+  const names = new Set(Object.keys(values))
+  return query.replace(/:(\w+)/g, (match, name) => {
+    return names.has(name) ? sanitize(values[name]) : match
+  })
+}
+
 function sanitize(value: Value): string {
   if (value == null) {
     return 'null'