[Javascript] Array methods in depth - some

some returns a boolean value after passing each item in the source array through the test function that you pass in as the first parameter. This makes it well suited to the types of queries that require a simple yes or no answer. In this lesson we look at 2 practical use-cases for some. The first shows how it can be used with a ternary operator to switch a class on an element & the second shows how some can be used in an if conditional.

 

 
var tasks = [
  {
    title: "A",
    completed: true
  },
  {
    title: "B",
    completed: false
  },
  {
    title: "C",
    completed: true
  }
];

function addTask(title) {
  if(tasks.some( task => task.title === title)){
    return ;
  }
  
  tasks.push({title: title, completed: false});
}

addTask('B');

console.log(tasks);

 

posted @ 2016-01-06 15:32  Zhentiw  阅读(135)  评论(0编辑  收藏  举报