@silverwind/ioredis-mock/lib/commands/linsert.js

This library emulates ioredis by performing all operations in-memory.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.linsert = linsert;

function linsert(key, position, pivot, element) {
  if (this.data.has(key) && !(this.data.get(key) instanceof Array)) {
    throw new Error(`Key ${key} does not contain a list`);
  }

  const list = this.data.get(key) || [];
  const pivotIndex = list.indexOf(pivot);
  if (pivotIndex < 0) return -1;
  let elementIndex = pivotIndex;

  switch (position) {
    case 'BEFORE':
      elementIndex = pivotIndex;
      break;

    case 'AFTER':
      elementIndex = pivotIndex + 1;
      break;

    default:
      throw new Error('The position of the new element must be BEFORE the pivot or AFTER the pivot');
  }

  list.splice(elementIndex, 0, element);
  const {
    length
  } = list;
  this.data.set(key, list);
  return length;
}