sylvamadu · April 4, 2022 10:26 · Mar 9, 2020 · Jul 30, 2019 · Feb 6, 2019 · Mar 15, 2017
diff --git a/filterArray.js b/filterArray.js
@@ -1,5 +1,5 @@
 /**
- * Filters an array of objects by custom predicates.
+ * Filters an array of objects using custom predicates.
  *
  * @param  {Array}  array: the array to filter
  * @param  {Object} filters: an object with the filter criteria
@@ -15,4 +15,26 @@ function filterArray(array, filters) {
       return filters[key](item[key]);
     });
   });
-}
+}
+
+/**
+ * The method `filterArray()` has the following signature:
+ *
+ * `function filterArray<TInput = any>(array: TInput[], filters: IFilters) => TInput[]`
+ *
+ * Where the function receives an array as the first argument, and a plain object
+ * describing the fields to filter as the last argument.
+ * The function returns an array of the same type as the input array.
+ *
+ * The signature of the filters arguments is the following:
+ *
+ * `interface IFilters {
+ *   [key: string]: (value: any) => boolean;
+ * }`
+ *
+ * Where the `filters` argument is an object that contains a `key: string`
+ * and its value is a function with the value of the property to evaluate.
+ * As the function predicate is evaluated using the `Array.prototype.every()` method,
+ * then it must return a boolean value, which will determine if the item
+ * must be included or not in the filtered array.
+ */
diff --git a/filterArray.test.js b/filterArray.test.js
@@ -13,6 +13,21 @@ describe('Testing filterArray()', () => {
       locations: locations => locations.find(x => ['JAPAN', 'USA'].includes(x.toUpperCase())),
       details: details => details.length < 30 && details.width >= 70,
     };
+
+    const filters = {
+      size: (size) => size === 50 || size === 70,
+      color: (color) => ['blue', 'black'].includes(color.toLowerCase()),
+      details: (details) => details.length < 30 && details.width >= 70,
+      locations: (locations) => {
+        if (locations.includes('USA')) return true; // case sensitive
+        if (locations.includes('Japan')) return true; // case sensitive
+
+        const url = window.location.pathname.toLowerCase();
+        if (url.includes('/en-us/')) return true; // not case sensitive
+        if (url.includes('/es/')) return true; // not case sensitive
+        return false;
+      }
+    };
 
     const filtered = filterArray(products, filters);
     const expected = [

diff --git a/filterArray.js b/filterArray.js
@@ -0,0 +1,18 @@
+/**
+ * Filters an array of objects by custom predicates.
+ *
+ * @param  {Array}  array: the array to filter
+ * @param  {Object} filters: an object with the filter criteria
+ * @return {Array}
+ */
+function filterArray(array, filters) {
+  const filterKeys = Object.keys(filters);
+  return array.filter(item => {
+    // validates all filter criteria
+    return filterKeys.every(key => {
+      // ignores non-function predicates
+      if (typeof filters[key] !== 'function') return true;
+      return filters[key](item[key]);
+    });
+  });
+}
diff --git a/filterArray.test.js b/filterArray.test.js
@@ -0,0 +1,24 @@
+describe('Testing filterArray()', () => {
+  it('should filter an array of objects by custom predicates', () => {
+    const products = [
+      { name: 'A', color: 'Blue', size: 50, locations: ['USA', 'Europe'], details: { length: 20, width: 70 } },
+      { name: 'B', color: 'Blue', size: 60, locations: [], details: { length: 20, width: 70 } },
+      { name: 'C', color: 'Black', size: 70, locations: ['Japan'], details: { length: 20, width: 71 } },
+      { name: 'D', color: 'Green', size: 50, locations: ['USA'], details: { length: 20, width: 71 } },
+    ];
+
+    const filters = {
+      size: size => size === 50 || size === 70,
+      color: color => ['blue', 'black'].includes(color.toLowerCase()),
+      locations: locations => locations.find(x => ['JAPAN', 'USA'].includes(x.toUpperCase())),
+      details: details => details.length < 30 && details.width >= 70,
+    };
+
+    const filtered = filterArray(products, filters);
+    const expected = [
+      { name: 'A', color: 'Blue', size: 50, locations: ['USA', 'Europe'], details: { length: 20, width: 70 } },
+      { name: 'C', color: 'Black', size: 70, locations: ['Japan'], details: { length: 20, width: 71 } },
+    ];
+    expect(filtered).toStrictEqual(expected);
+  });
+});
diff --git a/filterPlainArray.js b/filterPlainArray.js
@@ -0,0 +1,21 @@
+// ignores case-sensitive
+const getValue = value => (typeof value === 'string' ? value.toUpperCase() : value);
+
+/**
+ * Filters an array of objects (one level-depth) with multiple criteria.
+ *
+ * @param  {Array}  array: the array to filter
+ * @param  {Object} filters: an object with the filter criteria
+ * @return {Array}
+ */
+function filterPlainArray(array, filters) {
+  const filterKeys = Object.keys(filters);
+  return array.filter(item => {
+    // validates all filter criteria
+    return filterKeys.every(key => {
+      // ignores an empty filter
+      if (!filters[key].length) return true;
+      return filters[key].find(filter => getValue(filter) === getValue(item[key]));
+    });
+  });
+}
diff --git a/filterPlainArray.test.js b/filterPlainArray.test.js
@@ -0,0 +1,22 @@
+describe('Testing filterPlainArray()', () => {
+  it('should filter an array of objects with one level-depth', () => {
+    const products = [
+      { name: 'A', color: 'Blue', size: 50 },
+      { name: 'B', color: 'Blue', size: 60 },
+      { name: 'C', color: 'Black', size: 70 },
+      { name: 'D', color: 'Green', size: 50 },
+    ];
+
+    const filters = {
+      color: ['BLUE', 'black'],
+      size: [70, 50],
+    };
+
+    const filtered = filterPlainArray(products, filters);
+    const expected = [
+      { name: 'A', color: 'Blue', size: 50 },
+      { name: 'C', color: 'Black', size: 70 },
+    ];
+    expect(filtered).toStrictEqual(expected);
+  });
+});
diff --git a/multiFilter.js b/multiFilter.js
@@ -1,19 +0,0 @@
-/**
- * Filters an array of objects with multiple criteria.
- *
- * @param  {Array}  array: the array to filter
- * @param  {Object} filters: an object with the filter criteria as the property names
- * @return {Array}
- */
-function multiFilter(array, filters) {
-  const filterKeys = Object.keys(filters);
-  // filters all elements passing the criteria
-  return array.filter((item) => {
-    // dynamically validate all filter criteria
-    return filterKeys.every(key => {
-      // ignores an empty filter
-      if (!filters[key].length) return true;
-      return filters[key].includes(item[key]);
-    });
-  });
-}

diff --git a/test.js b/test.js
@@ -1,26 +0,0 @@
-let products = [
-  { name: "A", color: "Blue", size: 50 },
-  { name: "B", color: "Blue", size: 60 },
-  { name: "C", color: "Black", size: 70 },
-  { name: "D", color: "Green", size: 50 },
-];
-
-// the value of each key is an array with the values to filter
-let filters = {
-  color: ["Blue", "Black"],
-  size: [70, 50]
-};
-
-// filter the products array by color: blue and black
-// and also by size: 70 and 50
-var filtered = multiFilter(products, filters);
-
-console.info('Filtered:');
-console.log(filtered);
-
-/* expected
-[
-  { name: "A", color: "Blue", "size": 50 },
-  { name: "C", color: "Black", "size": 70 }
-]
-*/

diff --git a/multiFilter.js b/multiFilter.js
@@ -10,6 +10,10 @@ function multiFilter(array, filters) {
   // filters all elements passing the criteria
   return array.filter((item) => {
     // dynamically validate all filter criteria
-    return filterKeys.every(key => !!~filters[key].indexOf(item[key]));
+    return filterKeys.every(key => {
+      // ignores an empty filter
+      if (!filters[key].length) return true;
+      return filters[key].includes(item[key]);
+    });
   });
 }
diff --git a/multiFilter.js b/multiFilter.js
@@ -1,16 +1,15 @@
 /**
- * Multi-filter an array of objects
- * @param  {Array}  array  : list of elements to apply a multiple criteria filter
- * @param  {Object} filters: Contains multiple criteria filters by the property names of the objects to filter
+ * Filters an array of objects with multiple criteria.
+ *
+ * @param  {Array}  array: the array to filter
+ * @param  {Object} filters: an object with the filter criteria as the property names
  * @return {Array}
  */
 function multiFilter(array, filters) {
-  let filterKeys = Object.keys(filters);
+  const filterKeys = Object.keys(filters);
   // filters all elements passing the criteria
   return array.filter((item) => {
-    // validates all filters criteria dynamically
-    return filterKeys.every((key) => {
-      return (filters[key].indexOf(item[key]) !== -1);
-    });
+    // dynamically validate all filter criteria
+    return filterKeys.every(key => !!~filters[key].indexOf(item[key]));
   });
-}
+}
diff --git a/test.js b/test.js
@@ -1,23 +1,26 @@
 let products = [
   { name: "A", color: "Blue", size: 50 },
   { name: "B", color: "Blue", size: 60 },
-  { name: "C", color: "Black", size: 70 }
+  { name: "C", color: "Black", size: 70 },
+  { name: "D", color: "Green", size: 50 },
 ];
 
+// the value of each key is an array with the values to filter
 let filters = {
   color: ["Blue", "Black"],
   size: [70, 50]
 };
 
-// expected
-let expected = [
-  { name: "A", color: "Blue", "size": 50 },
-  { name: "C", color: "Black", "size": 70 }
-];
-
+// filter the products array by color: blue and black
+// and also by size: 70 and 50
 var filtered = multiFilter(products, filters);
 
-console.info('Expected');
-console.log(expected);
-console.info('Filtered');
-console.log(filtered);
+console.info('Filtered:');
+console.log(filtered);
+
+/* expected
+[
+  { name: "A", color: "Blue", "size": 50 },
+  { name: "C", color: "Black", "size": 70 }
+]
+*/
diff --git a/multiFilter.js b/multiFilter.js
@@ -0,0 +1,16 @@
+/**
+ * Multi-filter an array of objects
+ * @param  {Array}  array  : list of elements to apply a multiple criteria filter
+ * @param  {Object} filters: Contains multiple criteria filters by the property names of the objects to filter
+ * @return {Array}
+ */
+function multiFilter(array, filters) {
+  let filterKeys = Object.keys(filters);
+  // filters all elements passing the criteria
+  return array.filter((item) => {
+    // validates all filters criteria dynamically
+    return filterKeys.every((key) => {
+      return (filters[key].indexOf(item[key]) !== -1);
+    });
+  });
+}
diff --git a/test.js b/test.js
@@ -0,0 +1,23 @@
+let products = [
+  { name: "A", color: "Blue", size: 50 },
+  { name: "B", color: "Blue", size: 60 },
+  { name: "C", color: "Black", size: 70 }
+];
+
+let filters = {
+  color: ["Blue", "Black"],
+  size: [70, 50]
+};
+
+// expected
+let expected = [
+  { name: "A", color: "Blue", "size": 50 },
+  { name: "C", color: "Black", "size": 70 }
+];
+
+var filtered = multiFilter(products, filters);
+
+console.info('Expected');
+console.log(expected);
+console.info('Filtered');
+console.log(filtered);