promall/promall.js

Make creating and handling promises easy

'use strict'

const executeFunction = function (f, ...params){
  try{
    if(f instanceof Promise){
      return f;
    } else if(typeof f === 'function') {
      var res = f(...params);
      if(res instanceof Promise){
        return res;
      } else {
        return new Promise((resolve, reject) => {
          try{
            resolve(res);
          } catch (error) {
            reject(error);
          }
        });
      }
    } else {
      return new Promise((resolve, reject) => {
        try{
          resolve(f);
        } catch (error) {
          reject(error);
        }
      });
    }
  } catch (error) {
    if(exportFunction._doNotWrapErrors){
      console.error(error);
      throw error;
    } else {
      return new Promise((resolve, reject) => {
        reject(error);
      });
    }
  }
}

const awaitFunction = async function (f, ...params) {
  return await executeFunction(f, ...params);
}

const exportFunction = executeFunction;

exportFunction._doNotWrapErrors = false;
exportFunction.doNotWrapErrors = () => { exportFunction._doNotWrapErrors = true; };
exportFunction.await = awaitFunction;
exportFunction.promise = executeFunction;
exportFunction.execute = executeFunction;
exportFunction.wrapErrors = () => { exportFunction._doNotWrapErrors = false; };
exportFunction.wrap = (f) => {
  return function(...params) {
    return executeFunction(f, ...params);
  };
}
exportFunction.executeChain = function(chain, param){
  if(chain){
    return asynIter(chain, 0, param);
  } else {
    throw new Error('No promise function chain.');
  }
}

async function asynIter(list, index, input){
  if(list && index < list.length){
    var result = await list[index](input);
    if(result === undefined){
      result = input;
    }
    if(index + 1 === list.length){
      return result;
    } else {
      return asynIter(list, index + 1, result);
    }
  } else {
    return input;
  }
}

exportFunction.chain = exportFunction.executeChain;
exportFunction.all = function(...promises){
  if(promises){
    if(!Array.isArray(promises)){
      promises = [promises];
    }
    return Promise.all(promises);
  } else {
    throw new Error('No input given, cannot create Promise.all().');
  }
}

module.exports = executeFunction;