The avatar for @jtmccr1
JT McCrone
Published
Edited
Nov 18, 2020
Importers
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md`# date formatters`
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d3 = require("d3")
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function leapYear(year) {
return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
}
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yearFormat = d3.timeFormat("%Y")
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dayDemicalFormat = d3.timeFormat("j%")
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function dateToDecimal(date){
const year = parseInt(d3.timeFormat("%Y")(date));
const day = parseInt(d3.timeFormat("%j")(date));
const totalNumberOfDays = leapYear(year)? 366:365;
return year+day/totalNumberOfDays
}
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function decimalToDate(decimal){
const year = Math.trunc(decimal);
const totalNumberOfDays = leapYear(year)? 366:365;
const day = Math.round(((decimal-year)*totalNumberOfDays))
return d3.timeParse("%Y-%j")(`${year}-${day}`)

}
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formatDate =(f)=> (d) => {
const dateFormat = d3.timeFormat(f);
return `${dateFormat(decimalToDate(d))}`;
};

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decimalToDate((dateToDecimal(new Date)))
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parseFloat("2019-20")
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