PromiseResolveSpecial.js

var test = () => {
    new Promise((resolve, reject) => {
        resolve(undefined); // Will call then
    }).then(() => {
        console.log("Then");
    }).catch(() => {
        console.log("Catch");
    })
}

var test1 = () => {
    new Promise((resolve, reject) => {
        resolve(somethingNotDeclareYet); // Exception inside resolve => will call catch
    }).then(() => {
        console.log("Then");
    }).catch(() => {
        console.log("Catch");
    })
}

var test2 = () => {
    new Promise((resolve, reject) => {
        resolve(Promise.reject()); // Will call catch
    }).then(() => {
        console.log("Then");
    }).catch(() => {
        console.log("Catch");
    })
}

var test3 = () => {
    var doSomething = () => {
        throw new Error('Error')
    }
    new Promise((resolve, reject) => {
        resolve(doSomething()); // Will call Catch
    }).then(() => {
        console.log("Then");
    }).catch(() => {
        console.log("Catch");
    })
}


var test4 = () => {
    // All 3 promises will call catch

    var promise1 = Promise.resolve(Promise.reject())
        .catch((err) => {
            console.log(err); //undefined
        });

    var promise2 = Promise.resolve().then(function () {
        return Promise.reject();
    }).catch((err) => {
        console.log(err); //undefined
    });

    var promise3 = Promise.reject().catch(function () {
        return Promise.reject();
    }).catch((err) => {
        console.log(err); //undefined
    });

}