如何从包含日期范围的字符串中提取年份 [Typescript/Angular]

Question

I'm a beginner in Typescript. I have a date range which I'm receiving as a string.

var range="7-01-2018 VS 5-01-2019";

It is hard coded right now just to explain you. But it will be in this string form only later also. I've to extract 2018 and store it in some variable, say startYear and also I've to extract 2019 and store it in endYear variable. So that later I can compare them and apply validations.

I tried using:

1. substring(start,end)

My code worked but the problem is that the string will change its length when a double digit date is selected. For eg:

1. 7-01-2018 VS 25-01-2019 or
2. 17-01-2018 VS 5-01-2019 or
3. 27-01-2018 VS 25-01-2019

In these cases start and end will have different meanings. What should I do now. Please help me.

My method is:

myValidator() {

  range="7-01-2018 VS 5-01-2019";

  startYear=range.substring(5,8);

  endYear=range.substring(18,21);

  if(endYear<startYear) {
    console.log("Invalid range");
  }
}

Now I'm planning to use split() . And split the string into different parts and then write some logic with that. But the problem with split is that there's a VS in between. However for separator parameter i can give - symbol. Please correct me if I'm wrong.

Answer 1

• Using String.prototype.match

const range = '7-01-2018 VS 25-01-2019'


const [...range.matchAll(/\d{0,2}-\d{0,2}-(\d{0,4})/g)].map((date)=> date[1])

Answer 2

you are right split will be good

myValidator() {

      range="7-01-2018 VS 5-01-2019";

      startYear=parseInt(range.split("VS")[0].split("-")[2])

      endYear=parseInt(range.split("VS")[1].split("-")[2])

      if(endYear<startYear) {
        console.log("Invalid range");
      }
    }

Answer 3

全部在一条线上

const [,startYear,endYear]=range.match(/.*-(\d{4}) VS .*-(\d{4})$/);

Answer 4

Using split , Date and reduce :

 console.log("7-01-2018 VS 25-01-2019: ", checkRange("7-01-2018 VS 25-01-2019")); console.log("7-01-2019 VS 25-01-2018: ", checkRange("7-01-2019 VS 25-01-2018")); function checkRange(inputRange) { const range = inputRange.split(" VS "); const getYear = dateStr => new Date(dateStr.split("-").reverse().join("-")).getFullYear(); const years = range.reduce( (acc, val) => [...acc, getYear(val)], []); return years[0] < years[1]; }

 .as-console-wrapper { top: 0; max-height: 100% !important; }

Answer 5

Try this one, edited for array of integers as Output

myValidator() {
  range = "7-01-2018 VS 5-01-2019";
  regEx = /\d{4}/g;
  return (range.match(regEx).map(x => parseInt(x,10));
}
Output :
[ 2018, 2019 ]