timtnleeProject / lazy-utility

lazy-utility

Data

combineString

export const combineString = (...args) => {
  const [strs, ...exp] = args;
  let str = "";
  for (let i = 0; i < strs.length; i++) {
    if (exp[i]) {
      str += strs[i] + exp[i];
    } else if (i === strs.length - 1) {
      str += strs[i];
    }
  }
  return str;
};

Factory

CancelablePromise

export class CancelablePromise {
  constructor (originPromise) {
    this.cancelled = false;
    this.promises = [];
    originPromise
      .then(val => this.cancelled
        ? console.log("promise cancelled")
        : this.generateChains(Promise.resolve(val))
      )
      .catch(e => this.cancelled
        ? console.log("promise cancelled")
        : this.generateChains(Promise.reject(e))
      );
  }

  generateChains (first) {
    return this.promises.reduce((chains, handler) => {
      return chains[handler.type](handler.fn);
    }, first);
  }

  then (fn) {
    this.promises.push({
      type: "then",
      fn
    });
    return this;
  }

  catch (fn) {
    this.promises.push({
      type: "catch",
      fn
    });
    return this;
  }

  finally (fn) {
    this.promises.push({
      type: "finally",
      fn
    });
    return this;
  }

  cancel () {
    this.cancelled = true;
  }
}