[#2826] trim values before search (#2844)

* [#2826]trim values before searching

* [#2826]add test

* [#2826]add comment

cypress/integration/trim_values_before_search.spec.js

@@ -0,0 +1,43 @@
+describe('Trim values before search', () => {
+  beforeEach(() => {
+    cy.visit('/tests/index.html');
+  });
+
+  it('Matches even if there are leading and trailing spaces', () => {
+    cy.selectpicker({
+      html: `
+        <select class="selectpicker" data-live-search="true">
+          ${[
+            'apple',
+            'pear',
+            'dragon fruit'
+          ].map((value) =>
+            `<option value="${value}">${value}</option>`
+          ).join('')}}
+        </select>
+      `
+    }).then(($select) => {
+      const button = `[data-id="${$select[0].id}"]`;
+      cy.get(button).click();
+      $select.on('fetched.bs.select', cy.stub().as('fetched'));
+      [{
+        searchValue: ' app ',     // leading and trailing spaces
+        expectedContain: 'apple'
+      }, {
+        searchValue: ' 　pea',    // both half and full space mixed
+        expectedContain: 'pear'
+      }, {
+        searchValue: ' ',         // text with half-space also match
+        expectedContain: 'dragon fruit'
+      }].forEach((test) => {
+        cy.get('input').type(test.searchValue);
+        cy.get('.dropdown-menu').find('li').first().should(($el) => {
+          expect($el).to.have.class('active')
+          expect($el).to.contain(test.expectedContain);
+        });
+        cy.get('.dropdown-menu').find('li').first().click();
+        cy.get(button).contains(test.expectedContain).click();
+      });
+    });
+  });
+});

js/bootstrap-select.js

@@ -3007,6 +3007,11 @@
 
       this.$searchbox.on('input propertychange', function () {
         var searchValue = that.$searchbox[0].value;
+        var isWhitespace = /^\s*$/.test(searchValue);
+        if (!isWhitespace) {
+          // trim leading and trailing half-width spaces and full-width spaces.
+          searchValue = searchValue.replace(/^\s+|\s+$/g, '');
+        }
 
         that.selectpicker.search.elements = [];
         that.selectpicker.search.data = [];