shrink.js

// Response to https://stackoverflow.com/a/59556845

const shrink = (len) => (str) => {
  const words = str .split (' ')
  const idx = words .findIndex (
    (w, i) => words .slice(0, i) .join (' ') .length > len
  )
  return idx < 0 ? str : words .slice (0, idx - 1) .join ( ' ') + '...'
}

shrink (17) ("Hi you know anybody like pizza") //=> "Hi you know..."
shrink (20) ("Hi you know anybody like pizza") //=> "Hi you know anybody..."
shrink (50) ("Hi you know anybody like pizza") //=> "Hi you know anybody like pizza"


// Alternately, in a version that uses only expressions and not statement,
// but which is not suitable for being `mapped`, for instance:

/*
const shrink = (len) => (
  str,
  words = str .split (' '),
  idx = words .findIndex (
    (w, i) => words .slice(0, i) .join (' ') .length > len
  )
) => idx < 0 ? str : words .slice (0, idx - 1) .join ( ' ') + '...'
*/