PostgreSQL client for node.js designed for usage with ES7 async/await based on node-postgres (pg) module
npm install pg-async






Tiny but powerful Promise based PostgreSQL client for node.js
designed for easy use with ES7 async/await.
Based on node-postgres (known as pg in npm registry).
Can use pg or native pg-native backend.
``js
import PgAsync, {SQL} from 'pg-async';
// using default connection
const pgAsync = new PgAsync();
const userTable = 'user';
const sqlUserByLogin = (login) => SQL
select id
from $ID${userTable}
where login = ${login};
async function setPassword(login, newPwd) {
const userId = await pgAsync.value(sqlUserByLogin(login));
// userId is guaranted here,
// pgAsync.value requires query yielding exactly one row with one column.
await pgAsync.query(SQL
update $ID${userTable} set
passwd = ${newPwd}
where userId = ${userId}
);
}
`
``
$ npm install --save pg-async
#### Configuring Connection Options
`js`
new PgAsync([connectionOptions], [driver])
* The default export of pg-async is PgAsync class which let you configure connection optionspg.defaults
* Connection options defaults to driver
* Optional let you choose underlying librarynpm install --save pg-native
* To use the native bindings you must
`js
import PgAsync from 'pg-async';
// using default connection
const pgAsync = new PgAsync();
// using connection string
const pgAsync = new PgAsync('postgres://user:secret@host:port/database');
// using connection object
const pgAsync = new PgAsync({user, password, host, port, database, ...});
// using default for current user, with native driver
// install pg-native package manually
const pgAsync = new PgAsync(null, 'native');
const pgAsync = new PgAsync(null, require('pg').native);
`
---
#### `await pgAsync.query(SQL...) -> pg.Result`await pgAsync.query(sql, values...) -> pg.Result
#### await pgAsync.queryArgs(sql, [values]) -> pg.Result
####
* Execute SQL and return Result object from underlying pg libraryResult
* Interesting properties on object are:rowCount
* Number – returned rowsoid
* Number – Postgres oidrows
* Array – Actual result of pgAsync.rows()rowAsArray
* Booleanfields
* Array of:name
* String – name or alias of columntableID
* Number – oid of table or 0columnID
* Number – index of column in table or 0dataTypeID
* Number – oid of data typedataTypeSize
* Number – size in bytes od colum, -1 for variable lengthdataTypeModifier
* Number
---
#### `await pgAsync.rows(SQL...) -> array of objects`await pgAsync.rows(sql, values...) -> array of objects
#### await pgAsync.rowsArgs(sql, [values]) -> array of objects
####
* Execute SQL and return array of key/value objects (result.rows)
---
#### `await pgAsync.row(SQL...) -> object`await pgAsync.row(sql, values...) -> object
#### await pgAsync.rowArgs(sql, [values]) -> object
####
* Execute SQL and return single key/value object.
If query yields more than one or none rows, promise will be rejected.
* Rejected promise throw exception at await location.
---
#### `await pgAsync.value(SQL...) -> any`await pgAsync.value(sql, values...) -> any
#### await pgAsync.valueArgs(sql, [values]) -> any
####
* Same as row, but query must yields single column in single row, otherwise throws.
---
#### await pgAsync.connect(async (client) => innerResult) -> innerResult
* Execute multiple queries in sequence on same connection. This is handy for transactions.
* asyncFunc here has signature async (client, pgClient) => { ... }client
* provided has async methods:query
* , rows, row, value as abovequeryArgs
* , rowsArgs, rowArgs, valueArgs as abovestartTransaction
* , commit, rollback - start new transaction manually. Use pgAsync.transaction when possibleclient
* itself is shorthand for query
---
#### await pgAsync.transaction(async (client) => innerResult) -> innerResult
Transaction is similar to connect but automatically start and commit transaction,
rollback on throwen error
__Example:__
`js
const pgAsync = new PgAsync();
function moveMoney(fromAccount, toAccount, amount) {
return pgAsync.transaction(async (client) => {
let movementFrom, movementTo, movementId;
const sql =
INSERT INTO bank_account (account, amount)
VALUES ($1, $2)
RETURNS id
;
movementFrom = await client.value(sql, [fromAccount, -amount]);
movementTo = await client.value(sql, [toAccount, amount]);
return {movementFrom, movementTo}
});
}
async function doTheWork() {
// ...
try {
const result = await moveMoney('alice', 'bob', 19.95);
// transaction is commited
} catch (err) {
// transaction is rollbacked
}
// ...
}
`
---
#### await pgAsync.getClient([connectionOptions]) -> {client, done}
* Get unwrapped pg.Client callback based instance.done()
You should not call this method unless you know what are you doing.
* Client must be returned to pool manually by calling
---
#### pgAsync.closeConnections()
* Disconnects all idle clients within all active pools, and has all client pools terminate.
See pool.end()
* This actually terminates all connections on driver used by Pg instance
---
* [x] pg driver supportpg.native
* [x] driver supportdebug
* [x] — Enable debugging with DEBUG="pg-async" environment variableSAVEPOINT
* [x] Transaction API wrapper - Postgres does not support nested transactions
* [x] Template tag SQL formatting
* [ ] Transaction support
* [ ] Cursor API wrapper
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etc.
Copyright (c) 2016 Pavel Lang (langpavel@phpskelet.org)
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