problems(js): add “2675. Array of Objects to Matrix”

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/js/array-of-objects-to-matrix.js

@@ -0,0 +1,49 @@
+const isObject = x => x !== null && typeof x === 'object';
+
+const getKeys = object => {
+    if (!isObject(object)) {
+        return [''];
+    }
+
+    let result = [];
+
+    Object.keys(object).forEach(key => {
+        getKeys(object[key]).forEach(subKey => {
+            result.push(subKey ? `${key}.${subKey}` : key);
+        });
+    });
+
+    return result;
+};
+
+const getValue = (obj, path) => {
+    let [value, i, paths] = [obj, 0, path.split('.')];
+    for (i = 0; i < paths.length && isObject(value); ++i) {
+        value = value[paths[i]];
+    }
+
+    if (i < paths.length || value === undefined || isObject(value)) {
+        return '';
+    }
+
+    return value;
+};
+
+/**
+ * @param {Array} arr
+ * @return {Matrix}
+ */
+const jsonToMatrix = function(arr) {
+    let keySet = arr.reduce((keys, key) => {
+        getKeys(key).forEach(k => keys.add(k));
+        return keys;
+    }, new Set());
+
+    let keys = Array.from(keySet).sort();
+
+    let matrix = [keys];
+    arr.forEach(obj => {
+        matrix.push(keys.map(key => getValue(obj, key)));
+    });
+    return matrix;
+};