Add base token component, support for recents

- Adds BaseToken component which contains common
implementation for all tokens.
- Adds support for storing recently used token values
to localStorage.

app/assets/javascripts/vue_shared/components/filtered_search_bar/constants.js

 import { __ } from '~/locale';
 
 export const DEBOUNCE_DELAY = 200;
+export const MAX_RECENT_TOKENS_SIZE = 3;
 
 export const FILTER_NONE = 'None';
 export const FILTER_ANY = 'Any';

app/assets/javascripts/vue_shared/components/filtered_search_bar/filtered_search_utils.js

-import { isEmpty } from 'lodash';
+import { isEmpty, uniqWith, isEqual } from 'lodash';
+import AccessorUtilities from '~/lib/utils/accessor';
 import { queryToObject } from '~/lib/utils/url_utility';
 
+import { MAX_RECENT_TOKENS_SIZE } from './constants';
+
 /**
  * Strips enclosing quotations from a string if it has one.
  *
@@ -162,3 +165,38 @@ export function urlQueryToFilter(query = '') {
     return { ...memo, [filterName]: { value, operator } };
   }, {});
 }
+
+/**
+ * Returns array of token values from localStorage
+ * based on provided recentTokenValuesStorageKey
+ *
+ * @param {String} recentTokenValuesStorageKey
+ * @returns
+ */
+export function getRecentlyUsedTokenValues(recentTokenValuesStorageKey) {
+  let recentlyUsedTokenValues = [];
+  if (AccessorUtilities.isLocalStorageAccessSafe()) {
+    recentlyUsedTokenValues = JSON.parse(localStorage.getItem(recentTokenValuesStorageKey)) || [];
+  }
+  return recentlyUsedTokenValues;
+}
+
+/**
+ * Sets provided token value to recently used array
+ * within localStorage for provided recentTokenValuesStorageKey
+ *
+ * @param {String} recentTokenValuesStorageKey
+ * @param {Object} tokenValue
+ */
+export function setTokenValueToRecentlyUsed(recentTokenValuesStorageKey, tokenValue) {
+  const recentlyUsedTokenValues = getRecentlyUsedTokenValues(recentTokenValuesStorageKey);
+
+  recentlyUsedTokenValues.splice(0, 0, { ...tokenValue });
+
+  if (AccessorUtilities.isLocalStorageAccessSafe()) {
+    localStorage.setItem(
+      recentTokenValuesStorageKey,
+      JSON.stringify(uniqWith(recentlyUsedTokenValues, isEqual).slice(0, MAX_RECENT_TOKENS_SIZE)),
+    );
+  }
+}

app/assets/javascripts/vue_shared/components/filtered_search_bar/tokens/base_token.vue

+<script>
+import {
+  GlFilteredSearchToken,
+  GlFilteredSearchSuggestion,
+  GlDropdownDivider,
+  GlDropdownSectionHeader,
+  GlLoadingIcon,
+} from '@gitlab/ui';
+
+import { DEBOUNCE_DELAY } from '../constants';
+import { getRecentlyUsedTokenValues, setTokenValueToRecentlyUsed } from '../filtered_search_utils';
+
+export default {
+  components: {
+    GlFilteredSearchToken,
+    GlFilteredSearchSuggestion,
+    GlDropdownDivider,
+    GlDropdownSectionHeader,
+    GlLoadingIcon,
+  },
+  props: {
+    tokenConfig: {
+      type: Object,
+      required: true,
+    },
+    tokenValue: {
+      type: Object,
+      required: true,
+    },
+    tokenActive: {
+      type: Boolean,
+      required: true,
+    },
+    tokensListLoading: {
+      type: Boolean,
+      required: true,
+    },
+    tokenValues: {
+      type: Array,
+      required: true,
+    },
+    fnActiveTokenValue: {
+      type: Function,
+      required: true,
+    },
+    defaultTokenValues: {
+      type: Array,
+      required: false,
+      default: () => [],
+    },
+    recentTokenValuesStorageKey: {
+      type: String,
+      required: false,
+      default: '',
+    },
+    valueIdentifier: {
+      type: String,
+      required: false,
+      default: 'id',
+    },
+    fnCurrentTokenValue: {
+      type: Function,
+      required: false,
+      default: null,
+    },
+  },
+  data() {
+    return {
+      searchKey: '',
+      recentTokenValues: this.recentTokenValuesStorageKey
+        ? getRecentlyUsedTokenValues(this.recentTokenValuesStorageKey)
+        : [],
+      loading: false,
+    };
+  },
+  computed: {
+    isRecentTokenValuesEnabled() {
+      return Boolean(this.recentTokenValuesStorageKey);
+    },
+    recentTokenIds() {
+      return this.recentTokenValues.map((tokenValue) => tokenValue.id || tokenValue.name);
+    },
+    currentTokenValue() {
+      if (this.fnCurrentTokenValue) {
+        return this.fnCurrentTokenValue(this.tokenValue.data);
+      }
+      return this.tokenValue.data.toLowerCase();
+    },
+    activeTokenValue() {
+      return this.fnActiveTokenValue(this.tokenValues, this.currentTokenValue);
+    },
+    /**
+     * Return all the tokenValues when searchKey is present
+     * otherwise return only the tokenValues which aren't
+     * present in "Recently used"
+     */
+    availableTokenValues() {
+      return this.searchKey
+        ? this.tokenValues
+        : this.tokenValues.filter(
+            (tokenValue) => !this.recentTokenIds.includes(tokenValue[this.valueIdentifier]),
+          );
+    },
+  },
+  watch: {
+    tokenActive: {
+      immediate: true,
+      handler(newValue) {
+        if (!newValue && !this.tokenValues.length) {
+          this.$emit('fetch-token-values', this.tokenValue.data);
+        }
+      },
+    },
+  },
+  methods: {
+    handleInput({ data }) {
+      this.searchKey = data;
+      setTimeout(() => {
+        if (!this.tokensListLoading) this.$emit('fetch-token-values', data);
+      }, DEBOUNCE_DELAY);
+    },
+    handleTokenValueSelected(activeTokenValue) {
+      if (this.isRecentTokenValuesEnabled) {
+        setTokenValueToRecentlyUsed(this.recentTokenValuesStorageKey, activeTokenValue);
+      }
+    },
+  },
+};
+</script>
+
+<template>
+  <gl-filtered-search-token
+    :config="tokenConfig"
+    v-bind="{ ...this.$parent.$props, ...this.$parent.$attrs }"
+    v-on="this.$parent.$listeners"
+    @input="handleInput"
+    @select="handleTokenValueSelected(activeTokenValue)"
+  >
+    <template #view-token="viewTokenProps">
+      <slot name="view-token" :view-token-props="{ ...viewTokenProps, activeTokenValue }"></slot>
+    </template>
+    <template #view="viewTokenProps">
+      <slot name="view" :view-token-props="{ ...viewTokenProps, activeTokenValue }"></slot>
+    </template>
+    <template #suggestions>
+      <template v-if="defaultTokenValues.length">
+        <gl-filtered-search-suggestion
+          v-for="token in defaultTokenValues"
+          :key="token.value"
+          :value="token.value"
+        >
+          {{ token.text }}
+        </gl-filtered-search-suggestion>
+        <gl-dropdown-divider />
+      </template>
+      <template v-if="isRecentTokenValuesEnabled && recentTokenValues.length && !searchKey">
+        <gl-dropdown-section-header>{{ __('Recently used') }}</gl-dropdown-section-header>
+        <slot name="token-values-list" :token-values="recentTokenValues"></slot>
+        <gl-dropdown-divider />
+      </template>
+      <gl-loading-icon v-if="tokensListLoading" />
+      <template v-else>
+        <slot name="token-values-list" :token-values="availableTokenValues"></slot>
+      </template>
+    </template>
+  </gl-filtered-search-token>
+</template>

spec/frontend/vue_shared/components/filtered_search_bar/filtered_search_utils_spec.js

+import { useLocalStorageSpy } from 'helpers/local_storage_helper';
+
+import AccessorUtilities from '~/lib/utils/accessor';
 import {
   stripQuotes,
   uniqueTokens,
@@ -5,6 +8,8 @@ import {
   processFilters,
   filterToQueryObject,
   urlQueryToFilter,
+  getRecentlyUsedTokenValues,
+  setTokenValueToRecentlyUsed,
 } from '~/vue_shared/components/filtered_search_bar/filtered_search_utils';
 
 import {
@@ -14,6 +19,12 @@ import {
   tokenValuePlain,
 } from './mock_data';
 
+const mockStorageKey = 'recent-tokens';
+
+function setLocalStorageAvailability(isAvailable) {
+  jest.spyOn(AccessorUtilities, 'isLocalStorageAccessSafe').mockReturnValue(isAvailable);
+}
+
 describe('Filtered Search Utils', () => {
   describe('stripQuotes', () => {
     it.each`
@@ -249,3 +260,79 @@ describe('urlQueryToFilter', () => {
     expect(res).toEqual(result);
   });
 });
+
+describe('getRecentlyUsedTokenValues', () => {
+  useLocalStorageSpy();
+
+  beforeEach(() => {
+    localStorage.removeItem(mockStorageKey);
+  });
+
+  it('returns array containing recently used token values from provided recentTokenValuesStorageKey', () => {
+    setLocalStorageAvailability(true);
+
+    const mockExpectedArray = [{ foo: 'bar' }];
+    localStorage.setItem(mockStorageKey, JSON.stringify(mockExpectedArray));
+
+    expect(getRecentlyUsedTokenValues(mockStorageKey)).toEqual(mockExpectedArray);
+  });
+
+  it('returns empty array when provided recentTokenValuesStorageKey does not have anything in localStorage', () => {
+    setLocalStorageAvailability(true);
+
+    expect(getRecentlyUsedTokenValues(mockStorageKey)).toEqual([]);
+  });
+
+  it('returns empty array when when access to localStorage is not available', () => {
+    setLocalStorageAvailability(false);
+
+    expect(getRecentlyUsedTokenValues(mockStorageKey)).toEqual([]);
+  });
+});
+
+describe('setTokenValueToRecentlyUsed', () => {
+  const mockTokenValue1 = { foo: 'bar' };
+  const mockTokenValue2 = { bar: 'baz' };
+  useLocalStorageSpy();
+
+  beforeEach(() => {
+    localStorage.removeItem(mockStorageKey);
+  });
+
+  it('adds provided tokenValue to localStorage for recentTokenValuesStorageKey', () => {
+    setLocalStorageAvailability(true);
+
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue1);
+
+    expect(JSON.parse(localStorage.getItem(mockStorageKey))).toEqual([mockTokenValue1]);
+  });
+
+  it('adds provided tokenValue to localStorage at the top of existing values (i.e. Stack order)', () => {
+    setLocalStorageAvailability(true);
+
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue1);
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue2);
+
+    expect(JSON.parse(localStorage.getItem(mockStorageKey))).toEqual([
+      mockTokenValue2,
+      mockTokenValue1,
+    ]);
+  });
+
+  it('ensures that provided tokenValue is not added twice', () => {
+    setLocalStorageAvailability(true);
+
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue1);
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue1);
+
+    expect(JSON.parse(localStorage.getItem(mockStorageKey))).toEqual([mockTokenValue1]);
+  });
+
+  it('does not add any value when acess to localStorage is not available', () => {
+    setLocalStorageAvailability(false);
+
+    setTokenValueToRecentlyUsed(mockStorageKey, mockTokenValue1);
+
+    expect(JSON.parse(localStorage.getItem(mockStorageKey))).toBeNull();
+  });
+});

spec/frontend/vue_shared/components/filtered_search_bar/tokens/base_token_spec.js

+import { GlFilteredSearchToken } from '@gitlab/ui';
+import { mount } from '@vue/test-utils';
+import {
+  mockRegularLabel,
+  mockLabels,
+} from 'jest/vue_shared/components/sidebar/labels_select_vue/mock_data';
+
+import { DEFAULT_LABELS } from '~/vue_shared/components/filtered_search_bar/constants';
+import {
+  getRecentlyUsedTokenValues,
+  setTokenValueToRecentlyUsed,
+} from '~/vue_shared/components/filtered_search_bar/filtered_search_utils';
+import BaseToken from '~/vue_shared/components/filtered_search_bar/tokens/base_token.vue';
+
+import { mockLabelToken } from '../mock_data';
+
+jest.mock('~/vue_shared/components/filtered_search_bar/filtered_search_utils');
+
+const mockStorageKey = 'recent-tokens-label_name';
+
+const defaultStubs = {
+  Portal: true,
+  GlFilteredSearchToken: {
+    template: `
+      <div>
+        <slot name="view-token"></slot>
+        <slot name="view"></slot>
+      </div>
+    `,
+  },
+  GlFilteredSearchSuggestionList: {
+    template: '<div></div>',
+    methods: {
+      getValue: () => '=',
+    },
+  },
+};
+
+const defaultSlots = {
+  'view-token': `
+    <div class="js-view-token">${mockRegularLabel.title}</div>
+  `,
+  view: `
+    <div class="js-view">${mockRegularLabel.title}</div>
+  `,
+};
+
+const mockProps = {
+  tokenConfig: mockLabelToken,
+  tokenValue: { data: '' },
+  tokenActive: false,
+  tokensListLoading: false,
+  tokenValues: [],
+  fnActiveTokenValue: jest.fn(),
+  defaultTokenValues: DEFAULT_LABELS,
+  recentTokenValuesStorageKey: mockStorageKey,
+  fnCurrentTokenValue: jest.fn(),
+};
+
+function createComponent({
+  props = { ...mockProps },
+  stubs = defaultStubs,
+  slots = defaultSlots,
+} = {}) {
+  return mount(BaseToken, {
+    propsData: {
+      ...props,
+    },
+    provide: {
+      portalName: 'fake target',
+      alignSuggestions: jest.fn(),
+      suggestionsListClass: 'custom-class',
+    },
+    stubs,
+    slots,
+  });
+}
+
+describe('BaseToken', () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = createComponent({
+      props: {
+        ...mockProps,
+        tokenValue: { data: `"${mockRegularLabel.title}"` },
+        tokenValues: mockLabels,
+      },
+    });
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  describe('data', () => {
+    it('calls `getRecentlyUsedTokenValues` to populate `recentTokenValues` when `recentTokenValuesStorageKey` is defined', () => {
+      expect(getRecentlyUsedTokenValues).toHaveBeenCalledWith(mockStorageKey);
+    });
+  });
+
+  describe('computed', () => {
+    describe('currentTokenValue', () => {
+      it('calls `fnCurrentTokenValue` when it is provided', () => {
+        // We're disabling lint to trigger computed prop execution for this test.
+        // eslint-disable-next-line no-unused-vars
+        const { currentTokenValue } = wrapper.vm;
+
+        expect(wrapper.vm.fnCurrentTokenValue).toHaveBeenCalledWith(`"${mockRegularLabel.title}"`);
+      });
+    });
+
+    describe('activeTokenValue', () => {
+      it('calls `fnActiveTokenValue` when it is provided', async () => {
+        wrapper.setProps({
+          fnCurrentTokenValue: undefined,
+        });
+
+        await wrapper.vm.$nextTick();
+
+        // We're disabling lint to trigger computed prop execution for this test.
+        // eslint-disable-next-line no-unused-vars
+        const { activeTokenValue } = wrapper.vm;
+
+        expect(wrapper.vm.fnActiveTokenValue).toHaveBeenCalledWith(
+          mockLabels,
+          `"${mockRegularLabel.title.toLowerCase()}"`,
+        );
+      });
+    });
+  });
+
+  describe('watch', () => {
+    describe('tokenActive', () => {
+      let wrapperWithTokenActive;
+
+      beforeEach(() => {
+        wrapperWithTokenActive = createComponent({
+          props: {
+            ...mockProps,
+            tokenActive: true,
+            tokenValue: { data: `"${mockRegularLabel.title}"` },
+          },
+        });
+      });
+
+      afterEach(() => {
+        wrapperWithTokenActive.destroy();
+      });
+
+      it('emits `fetch-token-values` event on the component when value of this prop is changed to false and `tokenValues` array is empty', async () => {
+        wrapperWithTokenActive.setProps({
+          tokenActive: false,
+        });
+
+        await wrapperWithTokenActive.vm.$nextTick();
+
+        expect(wrapperWithTokenActive.emitted('fetch-token-values')).toBeTruthy();
+        expect(wrapperWithTokenActive.emitted('fetch-token-values')).toEqual([
+          [`"${mockRegularLabel.title}"`],
+        ]);
+      });
+    });
+  });
+
+  describe('methods', () => {
+    describe('handleTokenValueSelected', () => {
+      it('calls `setTokenValueToRecentlyUsed` when `recentTokenValuesStorageKey` is defined', () => {
+        const mockTokenValue = {
+          id: 1,
+          title: 'Foo',
+        };
+
+        wrapper.vm.handleTokenValueSelected(mockTokenValue);
+
+        expect(setTokenValueToRecentlyUsed).toHaveBeenCalledWith(mockStorageKey, mockTokenValue);
+      });
+    });
+  });
+
+  describe('template', () => {
+    it('renders gl-filtered-search-token component', () => {
+      const wrapperWithNoStubs = createComponent({
+        stubs: {},
+      });
+      const glFilteredSearchToken = wrapperWithNoStubs.find(GlFilteredSearchToken);
+
+      expect(glFilteredSearchToken.exists()).toBe(true);
+      expect(glFilteredSearchToken.props('config')).toBe(mockLabelToken);
+
+      wrapperWithNoStubs.destroy();
+    });
+
+    it('renders `view-token` slot when present', () => {
+      expect(wrapper.find('.js-view-token').exists()).toBe(true);
+    });
+
+    it('renders `view` slot when present', () => {
+      expect(wrapper.find('.js-view').exists()).toBe(true);
+    });
+
+    describe('events', () => {
+      let wrapperWithNoStubs;
+
+      beforeEach(() => {
+        wrapperWithNoStubs = createComponent({
+          stubs: { Portal: true },
+        });
+      });
+
+      afterEach(() => {
+        wrapperWithNoStubs.destroy();
+      });
+
+      it('emits `fetch-token-values` event on component after a delay when component emits `input` event', async () => {
+        jest.useFakeTimers();
+
+        wrapperWithNoStubs.find(GlFilteredSearchToken).vm.$emit('input', { data: 'foo' });
+        await wrapperWithNoStubs.vm.$nextTick();
+
+        jest.runAllTimers();
+
+        expect(wrapperWithNoStubs.emitted('fetch-token-values')).toBeTruthy();
+        expect(wrapperWithNoStubs.emitted('fetch-token-values')[1]).toEqual(['foo']);
+      });
+    });
+  });
+});