Gist of tags for template literals to 'pretty format' numbers

number_tags.js

/* Use:
  dec`1_234.5` // >> 1234.5
  oct`1_234` // >> 0o1234 === 668
  bin`0110_1100` // >> 0b01101100 === 108
  hex`A2_34` // >> 0xA234 === 41524
*/

// Heavily based on code by "Kusu"
const templateJoin = (strings, placeholders) => {
  const regex = /_/gu
  let result = strings[0]
  // DO NOT
  // I repeat
  // DO NOT use forEach
  // Use for (const [placeholder, i] of placeholders.entries())
  placeholders.forEach((placeholder, i) => {
    result += placeholder + strings[++i]
  })
  return result.replace(regex, ``)
}

const hex = ((strings, ...placeholders) => 
  Number(`0x${templateJoin(strings, placeholders)}`)
)
const dec = ((strings, ...placeholders) => 
  Number(templateJoin(strings, placeholders))
)

const oct = ((strings, ...placeholders) => 
  Number(`0o${templateJoin(strings, placeholders)}`)
)

const bin = ((strings, ...placeholders) => 
  Number(`0b${templateJoin(strings, placeholders)}`)
)