resolve:

    new Promise((resolve, reject) = > {
      setTimeout(() = > {
        resolve({ 
          code: 200})},500)
    }).then(res= > {
      console.log(res.code)
    })
Copy the code

reject:

    new Promise((resolve, reject) = > {
      setTimeout(() = > {
        reject({ 
          code: 400})},500)
    }).then(res= > {
      console.log(res.code)
    }, err= > {
      console.log(err.code)
    })
Copy the code

catch:

    new Promise((resolve, reject) = > {
      setTimeout(() = > {
        reject({ code: 400})},500)
    }).catch((err) = > {
      console.log(err.code)
    })
Copy the code

Resolve and catch:

    new Promise((resolve, reject) = > {
      setTimeout(() = > {
        if (Math.random() > 0.5) {
          resolve({ code: 200})}else {
          reject({ code: 400})}},500)
    })
      .then((res) = > {
        console.log(res.code)
      })
      .catch((err) = > {
        console.log(err.code)
      })
Copy the code

Throw:

    new Promise((resolve, reject) = > {
      throw new Error("Error")
    }).catch((err) = > {
      console.log(err.message)
    })
Copy the code