update more solutions

Author: someoneudonknow

Eazy/1603_DesignParkingSystem.js

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+/**
+ * @param {number} big
+ * @param {number} medium
+ * @param {number} small
+ */
+var ParkingSystem = function(big, medium, small) {
+    this.big = big;
+    this.medium = medium;
+    this.small = small;
+    this.space = {
+        big: 0,
+        medium: 0,
+        small: 0,
+    }
+};
+
+/** 
+ * @param {number} carType
+ * @return {boolean}
+ */
+ParkingSystem.prototype.addCar = function(carType) {
+    switch(carType) {
+        case 1:
+            if (this.space.big === this.big) {
+                return false;
+            }
+            this.space.big = this.space.big+1;
+            return true;
+        case 2:
+            if (this.space.medium === this.medium) {
+                return false;
+            }
+            this.space.medium = this.space.medium+1;
+            return true;
+        case 3:
+            if (this.space.small === this.small) {
+                return false;
+            }
+            this.space.small = this.space.small+1;
+            return true;
+        default: return false;
+    }
+};
+
+/** 
+ * Your ParkingSystem object will be instantiated and called as such:
+ * var obj = new ParkingSystem(big, medium, small)
+ * var param_1 = obj.addCar(carType)
+ */

Eazy/2695_ArrayWrapper.js

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+/**
+ * @param {number[]} nums
+ */
+var ArrayWrapper = function(nums) {
+    this.innerArray = nums
+};
+
+ArrayWrapper.prototype.valueOf = function() {
+    return this.innerArray.reduce((acc, val) => acc + val, 0)
+}
+
+ArrayWrapper.prototype.toString = function() {
+    return "[" + this.innerArray.join() + "]"
+}
+
+/**
+ * const obj1 = new ArrayWrapper([1,2]);
+ * const obj2 = new ArrayWrapper([3,4]);
+ * obj1 + obj2; // 10
+ * String(obj1); // "[1,2]"
+ * String(obj2); // "[3,4]"
+ */
+
+export default ArrayWrapper;

Medium/2625_FlattenDeeplyNestedArray.js

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+/**
+ * @param {any[]} arr
+ * @param {number} depth
+ * @return {any[]}
+ */
+var flat = function (arr, n) {
+    if(n === 0) {
+        return arr;
+    }
+    
+    let re = []
+    for(let el of arr) {
+        if(Array.isArray(el)) {
+            re.push(...flat(el, n-1)) ;
+        }else {
+            re.push(el)
+        }
+    }
+
+    return re
+};
+
+export default flat;

Medium/2631_GroupBy.js

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+/**
+ * @param {Function} fn
+ * @return {Array}
+ */
+Array.prototype.groupBy = function(fn) {
+    const groupedData = {};
+
+    for(const el of this) {
+        const key = fn(el);
+
+        if(!groupedData[key]) {
+            groupedData[key] = [el];
+        }else {
+            let currentData = groupedData[key];
+            currentData.push(el)
+            groupedData[key] = currentData;
+        }
+    }
+    
+    return groupedData;
+};
+
+/**
+ * [1,2,3].groupBy(String) // {"1":[1],"2":[2],"3":[3]}
+ */

Medium/2693_CallFunctionwithCustomContext.js

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+/**
+ * @param {Object} context
+ * @param {any[]} args
+ * @return {any}
+ */
+Function.prototype.callPolyfill = function(context, ...args) {
+    return this.call(context, ...args);
+}
+
+/**
+ * function increment() { this.count++; return this.count; }
+ * increment.callPolyfill({count: 1}); // 2
+ */

Medium/2694_EventEmitter.js

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+class EventEmitter {
+    eventOrder = 0;
+    eventList = [];
+    
+  subscribe(event, cb) {
+      const eventId = ++this.eventOrder;
+      
+     this.eventList.push({eid: eventId, eventItem: event, callback: cb});
+    return {
+        unsubscribe: () => {
+            return this.eventList.splice(this.eventList.indexOf(el => el.eid === eventId) - 1, 1);
+        }
+    };
+  }
+  emit(event, args = []) {
+    const currentEventList = this.eventList.filter(evt => evt.eventItem === event);
+    
+    const resultList = currentEventList.map(evt => evt.callback(...args));
+
+    return resultList;
+  }
+}
+
+/**
+ * const emitter = new EventEmitter();
+ *
+ * // Subscribe to the onClick event with onClickCallback
+ * function onClickCallback() { return 99 }
+ * const sub = emitter.subscribe('onClick', onClickCallback);
+ *
+ * emitter.emit('onClick'); // [99]
+ * sub.unsubscribe(); // undefined
+ * emitter.emit('onClick'); // []
+ */
+
+export default EventEmitter;