VikR VikR - 1 month ago 20
Node.js Question

Using Sequelize with ES6 Promises?

I'm using Sequelize to connect to a Postgres database. I have this code:

return Promise.resolve()
.then(() => {
console.log('checkpoint #1');
const temp = connectors.IM.create(args);
return temp;
})
.then((x) => console.log(x))
.then((args) =>{
console.log(args);
args = Array.from(args);
console.log('checkpoint #2');
const temp = connectors.IM.findAll({ where: args }).then((res) => res.map((item) => item.dataValues))
return temp;
}
)
.then(comment => {
return comment;
})
.catch((err)=>{console.log(err);});


In the first .then block at checkpoint #1, the new record is successfully added to the Postgres database. In the
console.log(x)
in the next then block, this gets logged to the console:

{ dataValues:
{ id: 21,
fromID: '1',
toID: '2',
msgText: 'Test from GraphIQL',
updatedAt: Wed Oct 12 2016 09:52:05 GMT-0700 (PDT),
createdAt: Wed Oct 12 2016 09:52:05 GMT-0700 (PDT) },
_previousDataValues:
{ fromID: '1',
toID: '2',
msgText: 'Test from GraphIQL',
id: 21,
createdAt: Wed Oct 12 2016 09:52:05 GMT-0700 (PDT),
updatedAt: Wed Oct 12 2016 09:52:05 GMT-0700 (PDT) },
_changed:
{ fromID: false,
toID: false,
msgText: false,
id: false,
createdAt: false,
updatedAt: false },
'$modelOptions':
{ timestamps: true,
instanceMethods: {},
classMethods: {},
validate: {},
freezeTableName: false,
underscored: false,
underscoredAll: false,
paranoid: false,
rejectOnEmpty: false,
whereCollection: null,
schema: null,
schemaDelimiter: '',
defaultScope: {},
scopes: [],
hooks: {},
indexes: [],
name: { plural: 'IMs', singular: 'IM' },
omitNul: false,
sequelize:
{ options: [Object],
config: [Object],
dialect: [Object],
models: [Object],
modelManager: [Object],
connectionManager: [Object],
importCache: {},
test: [Object],
queryInterface: [Object] },
uniqueKeys: {},
hasPrimaryKeys: true },
'$options':
{ isNewRecord: true,
'$schema': null,
'$schemaDelimiter': '',
attributes: undefined,
include: undefined,
raw: undefined,
silent: undefined },
hasPrimaryKeys: true,
__eagerlyLoadedAssociations: [],
isNewRecord: false }


In the
.then((args) =>
code block at checkpoint #2,
args
comes in as undefined.

How do I get args to contain an array of results from checkpoint #1?

Answer
.then((x) => console.log(x))
.then((args) =>{

is like doing

.then((x) => {
    console.log(x);

    return undefined;
})
.then((args) =>{

because console.log returns undefined. That means the undefined value will be what gets passed to the next .then.

The easiest approach would be to explicitly

.then((x) => {
    console.log(x);

    return x;
})

or in a shorter version using the comma operator

.then((x) => (console.log(x), x))