feat: predicate query POC implementation

Author: mdjastrzebski

src/queries/__tests__/predicate.test.tsx

@@ -0,0 +1,36 @@
+import React from 'react';
+import { View, Text, TextInput, Button } from 'react-native';
+import { ReactTestInstance } from 'react-test-renderer';
+import { render } from '../..';
+
+test('getByPredicate returns only native elements', () => {
+  const testIdPredicate = (testID: string) => (node: ReactTestInstance) => {
+    return node.props.testID === testID;
+  };
+
+  const { getByPredicate, getAllByPredicate } = render(
+    <View>
+      <Text testID="text">Text</Text>
+      <TextInput testID="textInput" />
+      <View testID="view" />
+      <Button testID="button" title="Button" onPress={jest.fn()} />
+    </View>
+  );
+
+  expect(getByPredicate(testIdPredicate('text'))).toBeTruthy();
+  expect(getByPredicate(testIdPredicate('textInput'))).toBeTruthy();
+  expect(getByPredicate(testIdPredicate('view'))).toBeTruthy();
+  expect(getByPredicate(testIdPredicate('button'))).toBeTruthy();
+
+  expect(getAllByPredicate(testIdPredicate('text'))).toHaveLength(1);
+  expect(getAllByPredicate(testIdPredicate('textInput'))).toHaveLength(1);
+  expect(getAllByPredicate(testIdPredicate('view'))).toHaveLength(1);
+  expect(getAllByPredicate(testIdPredicate('button'))).toHaveLength(1);
+
+  expect(() => getByPredicate(testIdPredicate('myComponent'))).toThrowError(
+    /^Unable to find an element matching predicate: /i
+  );
+  expect(() => getAllByPredicate(testIdPredicate('myComponent'))).toThrowError(
+    /^Unable to find an element matching predicate: /i
+  );
+});

src/queries/predicate.ts

@@ -0,0 +1,60 @@
+import type { ReactTestInstance } from 'react-test-renderer';
+import { makeQueries } from './makeQueries';
+import type {
+  FindAllByQuery,
+  FindByQuery,
+  GetAllByQuery,
+  GetByQuery,
+  QueryAllByQuery,
+  QueryByQuery,
+} from './makeQueries';
+
+type PredicateFn = (instance: ReactTestInstance) => boolean;
+// Not used so far
+type PredicateQueryOptions = void;
+
+const queryAllByPredicate = (
+  instance: ReactTestInstance
+): ((
+  predicate: PredicateFn,
+  options?: PredicateQueryOptions
+) => Array<ReactTestInstance>) =>
+  function queryAllByTestIdFn(predicate) {
+    const results = instance.findAll(
+      (node) => typeof node.type === 'string' && predicate(node)
+    );
+
+    return results;
+  };
+
+const getMultipleError = (predicate: PredicateFn) =>
+  `Found multiple elements matching predicate: ${predicate}`;
+
+const getMissingError = (predicate: PredicateFn) =>
+  `Unable to find an element matching predicate: ${predicate}`;
+
+const { getBy, getAllBy, queryBy, queryAllBy, findBy, findAllBy } = makeQueries(
+  queryAllByPredicate,
+  getMissingError,
+  getMultipleError
+);
+
+export type ByTestIdQueries = {
+  getByPredicate: GetByQuery<PredicateFn, PredicateQueryOptions>;
+  getAllByPredicate: GetAllByQuery<PredicateFn, PredicateQueryOptions>;
+  queryByPredicate: QueryByQuery<PredicateFn, PredicateQueryOptions>;
+  queryAllByPredicate: QueryAllByQuery<PredicateFn, PredicateQueryOptions>;
+  findByPredicate: FindByQuery<PredicateFn, PredicateQueryOptions>;
+  findAllByPredicate: FindAllByQuery<PredicateFn, PredicateQueryOptions>;
+};
+
+export const bindByPredicateQueries = (
+  instance: ReactTestInstance
+): ByTestIdQueries => ({
+  getByPredicate: getBy(instance),
+  getAllByPredicate: getAllBy(instance),
+  queryByPredicate: queryBy(instance),
+  queryAllByPredicate: queryAllBy(instance),
+  findByPredicate: findBy(instance),
+  findAllByPredicate: findAllBy(instance),
+});

src/within.ts

@@ -6,13 +6,15 @@ import { bindByDisplayValueQueries } from './queries/displayValue';
 import { bindByPlaceholderTextQueries } from './queries/placeholderText';
 import { bindUnsafeByTypeQueries } from './queries/unsafeType';
 import { bindUnsafeByPropsQueries } from './queries/unsafeProps';
+import { bindByPredicateQueries } from './queries/predicate';
 
 export function within(instance: ReactTestInstance) {
   return {
     ...bindByTextQueries(instance),
     ...bindByTestIdQueries(instance),
     ...bindByDisplayValueQueries(instance),
     ...bindByPlaceholderTextQueries(instance),
+    ...bindByPredicateQueries(instance),
     ...bindUnsafeByTypeQueries(instance),
     ...bindUnsafeByPropsQueries(instance),
     ...a11yAPI(instance),