30daysJS-18 - Tally String Times with Reduce
思路:
- 把字符串转为数字;
- 数字转为秒钟
- 秒钟重新计算小时分钟秒钟
数据处理:
- 获取节点伪数组,转为真数组;
- 使用
map方法遍历真数组,返回元素节点的dataset.time属性值,组成新数组; - 使用
map方法遍历新数组,将每个属性值- 使用
split()方法分割成[min,sec]形式构成的数组; - 对数组进行遍历,将
parseFloat()当作回调函数使用,将字符串转成数字,返回数字组成的数组; - 解构赋值:将数组内的两个元素分别赋值给
mins和secs - 使用两个新变量计算总秒数,返回总秒数值,构成秒数值组成的新数组;
- 使用
- 使用
reduce方法遍历秒数值构成的新数组,计算所有元素累积在一起的值总秒数,最终返回一个数字。 - 处理数字,计算小时,分钟,秒钟时间。
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<link rel="icon" href="https://fav.farm/✅" />
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<script>
const timeNodes = Array.from(document.querySelectorAll('[data-time]'));
const seconds = timeNodes
.map(node => node.dataset.time)
.map(timeCode => {
const [mins, secs] = timeCode.split(':').map(parseFloat);
return (mins * 60) + secs;
})
.reduce((total, vidSeconds) => total + vidSeconds);
let secondsLeft = seconds;
const hours = Math.floor(secondsLeft / 3600);
secondsLeft = secondsLeft % 3600;
const mins = Math.floor(secondsLeft / 60);
secondsLeft = secondsLeft % 60;
console.log(hours, mins, secondsLeft);
</script>
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