text: 
  const __interpose = (dst, dst_start, src, src_start, src_end, value) => {
  	const length = src_end - src_start
  	if (length === 0) { return }
  
  	let write_index = dst_start
  	let read_index = src_start
  
  	dst[write_index++] = src[read_index++]
  
  	while (read_index < src_end) {
  		dst[write_index++] = value
  		dst[write_index++] = src[read_index++]
  	}
  }
  
  const interpose = (arr, value) => {
  	const { length } = arr
  
  	if (length === 0) { return [] }
  
  	const res = new Array(length * 2 - 1)
  	__interpose(res, 0, arr, 0, length, value)
  	return res
  }
  
  module.exports = {
  	__interpose,
  	interpose,
  }
  