Some commonly used JavaScript methods

1. Determine whether it is a Node.js environment

 function isNode(){
    
    
    return typeof process !== 'undefined' && process.versions != null && process.versions.node != null;
}

Run in the browser, as shown above
Run in Node.js, as shown above

2. Parameter summation

Calculate the sum in the physical and chemical form of the function, and do it in one line of reduce

const sum = (...args) => args.reduce((a,b)=>a+b)

3.ES6 Set array deduplication

const uniqueArr = (arr) => [...new Set(arr)]

4. Randomly obtain a hexadecimal color

function getRandomColor(){
    
    
return `#${
      
      Math.floor(Math.random()*0xffffff).toString(16)}`
}

5. Move the last item of the array to the first

const setLastToFirst = (arr) => arr.unshift(arr.pop())

6. Hide the middle four digits of the mobile phone number through regular expressions

function hidePhone(tel){
    
    
    return tel.replace(/(\d{3})\d{4}(\d{4})/,'$1****$2')
}

7. Get a Boolean value randomly

The range of Math,random() is 0-0.99, and 0.5 is used to have a 50% probability in the middle.

function getRomBool(){
    
    
    return 0.5 > Math.random()
}

8. Extract the year, month, time, etc. in the time in one step

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