font-scaling-glamor-js.js

function cssGrad (p1, p2){
    // Based on y = mx + b
    let m = ((p2.y - p1.y) / (p2.x - p1.x)).toFixed(5)
    // Place space between "-" and number if negative
    m < 0 && (m = '- ' + (m * -1))
  
    // p1.y = (m * p1.x) + b
    let b = p1.y - (m * p1.x)
    // Place space between "-" and number if negative
    b < 0 ? b = '- ' + (b * -1).toFixed(2) : b = '+ ' + b.toFixed(2)
  
    return 'calc( ' + (m * 100).toFixed(2) + 'vw ' + b + 'px )'
}

const example = {
    fontSize: 36,
    // SCALE TO 45 @ 768
    '@media(min-width: 375px)': {
        fontSize: cssGrad({x:375, y: 36},{x:768, y: 45})
    },
    // SCALE TO 75 @ 1440
    '@media(min-width: 1024px)': {
        fontSize: cssGrad({x:1024, y: 53},{x: 1440, y: 75} )
}