init

JavaScript/ArrayOperation.md

@@ -0,0 +1,230 @@
+// ============数组扁平化得几种方法=============
+/**
+ * 使用reduce实现
+ * @param arr
+ * @returns {*}
+ */
+const flatten = (arr) => arr.reduce((result,item) => {
+  return result.concat(Array.isArray(item) ? flatten(item) : item)
+},[]);
+
+
+/**
+ * 通过join & split
+ * @param arr
+ * @returns {number[]} 使用Number转化为数值
+ */
+const flattenJoinSplit = (arr) => arr.join(',').split(',').map(item => parseInt(item));
+
+
+/**
+ * 通过toSting & split
+ * @param arr
+ * @returns {number[]} 使用Number转化为数值
+ */
+const flattenToStringSplit = (arr) => arr.toString().split(',').map(item => Number(item));
+
+
+/**
+ * 使用拓展运算符
+ * @param arr
+ * @returns {*}
+ */
+const flatten = (arr) => {
+  while(arr.some(item => Array.isArray(item))){
+    arr = [].concat(...arr)
+  }
+  return arr;
+}
+
+
+/**
+ * 随机化数组元素的顺序
+ * @param arr
+ * @returns {void }
+ */
+const shuffleArr = (arr) => arr.sort(() => Math.random() - 0.5);
+
+
+/**
+ * 删除数组元素中的重复元素
+ * @param arr
+ * @returns {unknown[]}
+ */
+const arrWithoutDupli = (arr) => [...new Set(arr)];
+
+
+/**
+ * 删除对象数组中的重复元素
+ * @type {{}}
+ */
+const obj = {};
+const arrObjectWithoutDupli = (arr, key) =>
+  arr.reduce((prev, cur) => {
+    if (!obj[cur[key]]) {
+      obj[cur[key]] = prev.push(cur);
+    }
+    return prev;
+  }, []);
+
+
+/**
+ * 获取两个数组之间不同的元素
+ * @param arr1
+ * @param arr2
+ * @returns {T[]}
+ */
+const arrDifference = (arr1,arr2) => arr1.concat(arr2).filter(v,i,arr) => arr.indexOf(v) === arr.lastIndexOf(v);
+
+
+/**
+ * 获取两个数组之间相同的元素
+ * @param arr1
+ * @param arr2
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const arrSimilarity = (arr1,arr2) => arr1.filter((v) => arr2.includes(v));
+
+
+/**
+ * 获取数组二 相对于数组一 不同的元素
+ * @param arr1
+ * @param arr2
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const getDifferenceFrom = (arr1,arr2) => {
+  const values = new Set(arr2);
+  return arr1.filter((element) => !values.has(element));
+};
+
+
+/**
+ * 获取数组中指定个数的最大元素
+ * @param arr
+ * @param n
+ * @returns {any[]}
+ */
+const maxArray = (arr,n = 1) => [...arr].sort((a,b) => b-a).slice(0,n);
+
+
+/**
+ * 获取数组中指定个数的最小元素
+ * @param arr
+ * @param n
+ * @returns {any[]}
+ */
+const minArray = (arr,n = 1) => [...arr].sort((a,b) => a-b).splice(0,n);
+
+
+/**
+ * 根据对象的键值在数组中查找对象
+ * @param arr
+ * @param key
+ * @param value
+ * @returns {*|number|bigint}
+ */
+const findObjectInArray = (arr,key,value) => arr.find((obj) => obj[key] === value);
+
+
+/**
+ * 根据元素值移除数组的元素
+ * @param arr
+ * @param el
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const arrRemoveEle = (arr,el) => arr.filter((i) => i !== el);
+
+
+/**
+ * 根据函数名称移除函数数组的元素
+ * @param arr
+ * @param name
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const arrRemoveFunEle = (arr,name) => arr.filter((i) => i.name !== name);
+
+
+/**
+ * 根据对象数组的属性值移除元素
+ * @param arr
+ * @param key
+ * @param value
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const arrRemoveObjEle = (arr,key,value) => arr.filter((i) => i[key] !==value);
+
+
+/**
+ * 计算对象数组指定的平均值
+ * @param arr
+ * @param key
+ * @returns {number}
+ */
+const averageBy = (arr,key) => arr.reduce((pre,cur) => pre + cur[key],0) / arr.length;
+
+
+/**
+ * 计算数组中元素的出现次数
+ * @param arr
+ * @param value
+ * @returns {*}
+ */
+const countFrequency = (arr,value) => arr.reduce((pre,cur) => (cur === value ? pre + 1 : pre + 0),0);
+
+
+/**
+ * 计算对象数组中某个属性值的出现次数
+ * @param arr
+ * @param key
+ * @param value
+ * @returns {*}
+ */
+const countObjFrequency = (arr,key,value) => arr.reduce((pre,cur) => (cur[key] === value ? pre + 1 : pre + 0),0);
+
+
+/**
+ * 计算数组元素的总和
+ * @param arr
+ * @returns {*}
+ */
+const getTotal = (arr) => arr.reduce((pre,cur) => pre + cur,0);
+
+
+/**
+ * 计算对象数组某个属性值的总和
+ * @param arr
+ * @param key
+ * @returns {*}
+ */
+const getTotalBy = (arr,key) => arr.reduce((pre,cur) => pre + cur[key],0);
+
+
+/**
+ * 过滤数组中的非唯一值
+ * @param arr
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const filterNoUnique = (arr) => arr.filter((i) => arr.indexOf(i) === arr.lastIndexOf(i));
+
+
+/**
+ * 过滤数组中的唯一值
+ * @param arr
+ * @returns {Int32Array | * | Uint32Array | any[] | Int8Array | Float64Array | BigUint64Array | Uint8Array | Int16Array | BigInt64Array | Float32Array | Uint8ClampedArray | Uint16Array}
+ */
+const filterUnique = (arr) => arr.filter((i) => arr.indexOf(i) !== arr.lastIndexOf(i));
+
+
+/**
+ * 检测数组中所有元素是否符合要求
+ * @param arr
+ * @param fn
+ * @returns {boolean}
+ */
+const isAllPass = (arr,fn) => arr.every(fn);
+
+
+
+
+
+