chore: improve invalid custom operators error message

Author: josdejong

src/operators.ts

@@ -1,4 +1,5 @@
 import type { CustomOperator, OperatorGroup } from './types'
+import { isArray } from './is'
 
 // operator precedence from highest to lowest
 export const operators: OperatorGroup[] = [
@@ -12,6 +13,11 @@ export const operators: OperatorGroup[] = [
 ]
 
 export function extendOperators(operators: OperatorGroup[], newOperators: CustomOperator[]) {
+  // backward compatibility error with v4 where `operators` was an object
+  if (!isArray(newOperators)) {
+    throw new Error('Invalid custom operators')
+  }
+
   return newOperators.reduce(extendOperator, operators)
 }
 

src/parse.test.ts

@@ -57,6 +57,24 @@ describe('customization', () => {
     expect(parse('.score ~= 8', options)).toEqual(['aboutEq', ['get', 'score'], 8])
     expect(parse('.score == 8', options)).toEqual(['eq', ['get', 'score'], 8])
   })
+
+  test('should throw an error in case of an invalid custom operator', () => {
+    const options: JSONQueryParseOptions = {
+      // @ts-ignore
+      operators: [{}]
+    }
+
+    expect(() => parse('.score > 8', options)).toThrow('Invalid custom operator')
+  })
+
+  test('should throw an error in case of an invalid custom operator (2)', () => {
+    const options: JSONQueryParseOptions = {
+      // @ts-ignore
+      operators: {}
+    }
+
+    expect(() => parse('.score > 8', options)).toThrow('Invalid custom operators')
+  })
 })
 
 describe('test-suite', () => {