数组常用方法总结

1.  判断数组中是否存在某个值

   var arrData = ['html', 'css', 'javascript'];
   var value = 'css';
   
   console.log(arrData.includes(value));
   console.log(arrData.some(item => item === value));
   console.log(arrData.indexOf(value) < 0 ? false : true);
   console.log(arrData.findIndex(item => item === value) < 0 ? false : true);
   console.log(arrData.find(item => item === value) !== undefined ? true : false );

   var arrData = [{ name: 'html' }, { name: 'css' }, { name: 'javascript' }];
   var value = 'css';
   
   console.log(arrData.some(item => item.name === value));
   console.log(arrData.filter(item=> item.name === value)[0] ? true : false);
   console.log(arrData.find(item => item.name === value) ? true : false);

2.  数组去重

   var arrData = ['html', 'css', 'javascript', 'css'];
   
   console.log([...new Set(arrData)]);
   console.log(Array.from(new Set(arrData)));
   console.log(arrData.filter((item, index, slef) => slef.indexOf(item) === index));
   console.log(arrData.reduce((prev, cur) => prev.includes(cur) ? prev : [...prev, cur], []));