JS関数式プログラミング例(高次関数応用)

    //JavaScript    ，             ====>>>     
    //1.filter   ，         ，    boolean 
    const nums = [10, 20, 30, 40, 50, 60];
    //let numbers = nums.filter(n=>n>20);
    //console.log(numbers);

    //2.map   
    //let numbers = nums.map(item => item * 2);
    //console.log(numbers);

    //3.reduce    
    //let numbers = nums.reduce(((previousValue, currentValue) => previousValue + currentValue),1);
    //console.log(numbers);
    let numbers = nums.filter(item => item > 50).map(item => item * 2).reduce((previousValue, currentValue) => previousValue + currentValue);
    console.log(numbers);