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Provider

scrypt-ts / Provider

Class: Provider

A Provider is an abstraction of non-account-based operations on a blockchain and is generally not directly involved in signing transaction or data.

Hierarchy​

Table of contents​

Constructors​

Properties​

Methods​

Constructors​

constructor​

• new Provider()

Overrides​

EventEmitter.constructor

Defined in​

dist/bsv/abstract-provider.d.ts:32

Properties​

_isProvider​

• Readonly _isProvider: boolean

Defined in​

dist/bsv/abstract-provider.d.ts:96

captureRejectionSymbol​

▪ Static Readonly captureRejectionSymbol: typeof captureRejectionSymbol

Inherited from​

EventEmitter.captureRejectionSymbol

Defined in​

node_modules/@types/node/events.d.ts:357

captureRejections​

▪ Static captureRejections: boolean

Sets or gets the default captureRejection value for all emitters.

Inherited from​

EventEmitter.captureRejections

Defined in​

node_modules/@types/node/events.d.ts:362

defaultMaxListeners​

▪ Static defaultMaxListeners: number

Inherited from​

EventEmitter.defaultMaxListeners

Defined in​

node_modules/@types/node/events.d.ts:363

errorMonitor​

▪ Static Readonly errorMonitor: typeof errorMonitor

This symbol shall be used to install a listener for only monitoring 'error' events. Listeners installed using this symbol are called before the regular 'error' listeners are called.

Installing a listener using this symbol does not change the behavior once an 'error' event is emitted, therefore the process will still crash if no regular 'error' listener is installed.

Inherited from​

EventEmitter.errorMonitor

Defined in​

node_modules/@types/node/events.d.ts:356

Methods​

addListener​

▸ addListener(eventName, listener): Provider

Alias for emitter.on(eventName, listener).

Since

v0.1.26

Parameters​

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns​

Provider

Inherited from​

EventEmitter.addListener

Defined in​

node_modules/@types/node/events.d.ts:383

connect​

▸ Abstract connect(): Promise<Provider>

Implement the connection provider, for example, verify the api key during the connection process.

Returns​

Promise<Provider>

a connected provider. Throw an exception if the connection fails.

Defined in​

dist/bsv/abstract-provider.d.ts:41

emit​

▸ emit(eventName, ...args): boolean

Synchronously calls each of the listeners registered for the event namedeventName, in the order they were registered, passing the supplied arguments to each.

Returns true if the event had listeners, false otherwise.

const EventEmitter = require('events');
const myEmitter = new EventEmitter();

// First listener
myEmitter.on('event', function firstListener() {
  console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
  console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
  const parameters = args.join(', ');
  console.log(`event with parameters ${parameters} in third listener`);
});

console.log(myEmitter.listeners('event'));

myEmitter.emit('event', 1, 2, 3, 4, 5);

// Prints:
// [
//   [Function: firstListener],
//   [Function: secondListener],
//   [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listener

Since

v0.1.26

Parameters​

NameType
eventNamestring | symbol
...argsany[]

Returns​

boolean

Inherited from​

EventEmitter.emit

Defined in​

node_modules/@types/node/events.d.ts:639

eventNames​

▸ eventNames(): (string | symbol)[]

Returns an array listing the events for which the emitter has registered listeners. The values in the array are strings or Symbols.

const EventEmitter = require('events');
const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});

const sym = Symbol('symbol');
myEE.on(sym, () => {});

console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]

Since

v6.0.0

Returns​

(string | symbol)[]

Inherited from​

EventEmitter.eventNames

Defined in​

node_modules/@types/node/events.d.ts:702

getBalance​

▸ Abstract getBalance(address?): Promise<{ confirmed: number ; unconfirmed: number }>

Get the balance of BSVs in satoshis for an address.

Parameters​

NameTypeDescription
address?AddressThe query address.

Returns​

Promise<{ confirmed: number ; unconfirmed: number }>

A promise which resolves to the address balance status.

Defined in​

dist/bsv/abstract-provider.d.ts:92

getEstimateFee​

▸ getEstimateFee(tx): Promise<number>

Get a best guess of the fee for a transaction.

Parameters​

NameTypeDescription
txTransactionA transaction object to estimate.

Returns​

Promise<number>

The estimated fee in satoshis.

Defined in​

dist/bsv/abstract-provider.d.ts:60

getFeePerKb​

▸ Abstract getFeePerKb(): Promise<number>

Returns​

Promise<number>

The fee rate for sending transactions through this provider.

Defined in​

dist/bsv/abstract-provider.d.ts:54

getMaxListeners​

▸ getMaxListeners(): number

Returns the current max listener value for the EventEmitter which is either set by emitter.setMaxListeners(n) or defaults to defaultMaxListeners.

Since

v1.0.0

Returns​

number

Inherited from​

EventEmitter.getMaxListeners

Defined in​

node_modules/@types/node/events.d.ts:555

getNetwork​

▸ Abstract getNetwork(): Network

Returns​

Network

The network this provider is connected to.

Defined in​

dist/bsv/abstract-provider.d.ts:50

getTransaction​

▸ Abstract getTransaction(txHash): Promise<TransactionResponse>

Get a transaction from the network.

Parameters​

NameTypeDescription
txHashstringThe hash value of the transaction.

Returns​

Promise<TransactionResponse>

The query result with the transaction information.

Defined in​

dist/bsv/abstract-provider.d.ts:79

isConnected​

▸ Abstract isConnected(): boolean

check if provider is ready

Returns​

boolean

Defined in​

dist/bsv/abstract-provider.d.ts:36

listUnspent​

▸ Abstract listUnspent(address, options?): Promise<IUnspentOutput[]>

Get a list of the P2PKH UTXOs.

Parameters​

NameTypeDescription
addressAddressThe address of the returned UTXOs belongs to.
options?UtxoQueryOptionsThe optional query conditions, see details in UtxoQueryOptions.

Returns​

Promise<IUnspentOutput[]>

A promise which resolves to a list of UTXO for the query options.

Defined in​

dist/bsv/abstract-provider.d.ts:86

listenerCount​

▸ listenerCount(eventName, listener?): number

Returns the number of listeners listening to the event named eventName.

If listener is provided, it will return how many times the listener is found in the list of the listeners of the event.

Since

v3.2.0

Parameters​

NameTypeDescription
eventNamestring | symbolThe name of the event being listened for
listener?FunctionThe event handler function

Returns​

number

Inherited from​

EventEmitter.listenerCount

Defined in​

node_modules/@types/node/events.d.ts:649

listeners​

▸ listeners(eventName): Function[]

Returns a copy of the array of listeners for the event named eventName.

server.on('connection', (stream) => {
  console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]

Since

v0.1.26

Parameters​

NameType
eventNamestring | symbol

Returns​

Function[]

Inherited from​

EventEmitter.listeners

Defined in​

node_modules/@types/node/events.d.ts:568

off​

▸ off(eventName, listener): Provider

Alias for emitter.removeListener().

Since

v10.0.0

Parameters​

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns​

Provider

Inherited from​

EventEmitter.off

Defined in​

node_modules/@types/node/events.d.ts:528

on​

▸ on(eventName, listener): Provider

Adds the listener function to the end of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventNameand listener will result in the listener being added, and called, multiple times.

server.on('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. Theemitter.prependListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

const myEE = new EventEmitter();
myEE.on('foo', () => console.log('a'));
myEE.prependListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Since

v0.1.101

Parameters​

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns​

Provider

Inherited from​

EventEmitter.on

Defined in​

node_modules/@types/node/events.d.ts:414

once​

▸ once(eventName, listener): Provider

Adds a one-timelistener function for the event named eventName. The next time eventName is triggered, this listener is removed and then invoked.

server.once('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

By default, event listeners are invoked in the order they are added. Theemitter.prependOnceListener() method can be used as an alternative to add the event listener to the beginning of the listeners array.

const myEE = new EventEmitter();
myEE.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
//   b
//   a

Since

v0.3.0

Parameters​

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns​

Provider

Inherited from​

EventEmitter.once

Defined in​

node_modules/@types/node/events.d.ts:443

prependListener​

▸ prependListener(eventName, listener): Provider

Adds the listener function to the beginning of the listeners array for the event named eventName. No checks are made to see if the listener has already been added. Multiple calls passing the same combination of eventNameand listener will result in the listener being added, and called, multiple times.

server.prependListener('connection', (stream) => {
  console.log('someone connected!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v6.0.0

Parameters​

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns​

Provider

Inherited from​

EventEmitter.prependListener

Defined in​

node_modules/@types/node/events.d.ts:667

prependOnceListener​

▸ prependOnceListener(eventName, listener): Provider

Adds a one-timelistener function for the event named eventName to the beginning of the listeners array. The next time eventName is triggered, this listener is removed, and then invoked.

server.prependOnceListener('connection', (stream) => {
  console.log('Ah, we have our first user!');
});

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v6.0.0

Parameters​

NameTypeDescription
eventNamestring | symbolThe name of the event.
listener(...args: any[]) => voidThe callback function

Returns​

Provider

Inherited from​

EventEmitter.prependOnceListener

Defined in​

node_modules/@types/node/events.d.ts:683

rawListeners​

▸ rawListeners(eventName): Function[]

Returns a copy of the array of listeners for the event named eventName, including any wrappers (such as those created by .once()).

const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));

// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];

// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();

// Logs "log once" to the console and removes the listener
logFnWrapper();

emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');

// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');

Since

v9.4.0

Parameters​

NameType
eventNamestring | symbol

Returns​

Function[]

Inherited from​

EventEmitter.rawListeners

Defined in​

node_modules/@types/node/events.d.ts:598

removeAllListeners​

▸ removeAllListeners(event?): Provider

Removes all listeners, or those of the specified eventName.

It is bad practice to remove listeners added elsewhere in the code, particularly when the EventEmitter instance was created by some other component or module (e.g. sockets or file streams).

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.1.26

Parameters​

NameType
event?string | symbol

Returns​

Provider

Inherited from​

EventEmitter.removeAllListeners

Defined in​

node_modules/@types/node/events.d.ts:539

removeListener​

▸ removeListener(eventName, listener): Provider

Removes the specified listener from the listener array for the event namedeventName.

const callback = (stream) => {
  console.log('someone connected!');
};
server.on('connection', callback);
// ...
server.removeListener('connection', callback);

removeListener() will remove, at most, one instance of a listener from the listener array. If any single listener has been added multiple times to the listener array for the specified eventName, then removeListener() must be called multiple times to remove each instance.

Once an event is emitted, all listeners attached to it at the time of emitting are called in order. This implies that anyremoveListener() or removeAllListeners() calls after emitting and before the last listener finishes execution will not remove them fromemit() in progress. Subsequent events behave as expected.

const myEmitter = new MyEmitter();

const callbackA = () => {
  console.log('A');
  myEmitter.removeListener('event', callbackB);
};

const callbackB = () => {
  console.log('B');
};

myEmitter.on('event', callbackA);

myEmitter.on('event', callbackB);

// callbackA removes listener callbackB but it will still be called.
// Internal listener array at time of emit [callbackA, callbackB]
myEmitter.emit('event');
// Prints:
//   A
//   B

// callbackB is now removed.
// Internal listener array [callbackA]
myEmitter.emit('event');
// Prints:
//   A

Because listeners are managed using an internal array, calling this will change the position indices of any listener registered after the listener being removed. This will not impact the order in which listeners are called, but it means that any copies of the listener array as returned by the emitter.listeners() method will need to be recreated.

When a single function has been added as a handler multiple times for a single event (as in the example below), removeListener() will remove the most recently added instance. In the example the once('ping')listener is removed:

const ee = new EventEmitter();

function pong() {
  console.log('pong');
}

ee.on('ping', pong);
ee.once('ping', pong);
ee.removeListener('ping', pong);

ee.emit('ping');
ee.emit('ping');

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.1.26

Parameters​

NameType
eventNamestring | symbol
listener(...args: any[]) => void

Returns​

Provider

Inherited from​

EventEmitter.removeListener

Defined in​

node_modules/@types/node/events.d.ts:523

sendRawTransaction​

▸ Abstract sendRawTransaction(rawTxHex): Promise<string>

Send a raw transaction hex string.

Parameters​

NameTypeDescription
rawTxHexstringThe raw transaction hex string to send.

Returns​

Promise<string>

A promise which resolves to the hash of the transaction that has been sent.

Defined in​

dist/bsv/abstract-provider.d.ts:66

sendTransaction​

▸ sendTransaction(tx): Promise<string>

Send a transaction object.

Throws

If there is a problem with the tx object during serialization.

Parameters​

NameTypeDescription
txTransactionThe transaction object to send.

Returns​

Promise<string>

A promise which resolves to the hash of the transaction that has been sent.

Defined in​

dist/bsv/abstract-provider.d.ts:73

setMaxListeners​

▸ setMaxListeners(n): Provider

By default EventEmitters will print a warning if more than 10 listeners are added for a particular event. This is a useful default that helps finding memory leaks. The emitter.setMaxListeners() method allows the limit to be modified for this specific EventEmitter instance. The value can be set toInfinity (or 0) to indicate an unlimited number of listeners.

Returns a reference to the EventEmitter, so that calls can be chained.

Since

v0.3.5

Parameters​

NameType
nnumber

Returns​

Provider

Inherited from​

EventEmitter.setMaxListeners

Defined in​

node_modules/@types/node/events.d.ts:549

updateNetwork​

▸ Abstract updateNetwork(network): void

update provider network

Parameters​

NameTypeDescription
networkNetworkNetwork type to be updated

Returns​

void

Defined in​

dist/bsv/abstract-provider.d.ts:46

getEventListeners​

▸ Static getEventListeners(emitter, name): Function[]

Returns a copy of the array of listeners for the event named eventName.

For EventEmitters this behaves exactly the same as calling .listeners on the emitter.

For EventTargets this is the only way to get the event listeners for the event target. This is useful for debugging and diagnostic purposes.

const { getEventListeners, EventEmitter } = require('events');

{
  const ee = new EventEmitter();
  const listener = () => console.log('Events are fun');
  ee.on('foo', listener);
  getEventListeners(ee, 'foo'); // [listener]
}
{
  const et = new EventTarget();
  const listener = () => console.log('Events are fun');
  et.addEventListener('foo', listener);
  getEventListeners(et, 'foo'); // [listener]
}

Since

v15.2.0, v14.17.0

Parameters​

NameType
emitterEventEmitter | _DOMEventTarget
namestring | symbol

Returns​

Function[]

Inherited from​

EventEmitter.getEventListeners

Defined in​

node_modules/@types/node/events.d.ts:299

getMaxListeners​

▸ Static getMaxListeners(emitter): number

Returns the currently set max amount of listeners.

For EventEmitters this behaves exactly the same as calling .getMaxListeners on the emitter.

For EventTargets this is the only way to get the max event listeners for the event target. If the number of event handlers on a single EventTarget exceeds the max set, the EventTarget will print a warning.

import { getMaxListeners, setMaxListeners, EventEmitter } from 'node:events';

{
  const ee = new EventEmitter();
  console.log(getMaxListeners(ee)); // 10
  setMaxListeners(11, ee);
  console.log(getMaxListeners(ee)); // 11
}
{
  const et = new EventTarget();
  console.log(getMaxListeners(et)); // 10
  setMaxListeners(11, et);
  console.log(getMaxListeners(et)); // 11
}

Since

v18.17.0

Parameters​

NameType
emitterEventEmitter | _DOMEventTarget

Returns​

number

Inherited from​

EventEmitter.getMaxListeners

Defined in​

node_modules/@types/node/events.d.ts:328

isProvider​

▸ Static isProvider(value): value is Provider

Check if an object is a Provider

Parameters​

NameTypeDescription
valueanyThe target object

Returns​

value is Provider

Returns true if and only if object is a Provider.

Defined in​

dist/bsv/abstract-provider.d.ts:102

listenerCount​

▸ Static listenerCount(emitter, eventName): number

A class method that returns the number of listeners for the given eventNameregistered on the given emitter.

const { EventEmitter, listenerCount } = require('events');
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2

Since

v0.9.12

Deprecated

Since v3.2.0 - Use listenerCount instead.

Parameters​

NameTypeDescription
emitterEventEmitterThe emitter to query
eventNamestring | symbolThe event name

Returns​

number

Inherited from​

EventEmitter.listenerCount

Defined in​

node_modules/@types/node/events.d.ts:271

on​

▸ Static on(emitter, eventName, options?): AsyncIterableIterator<any>

const { on, EventEmitter } = require('events');

(async () => {
  const ee = new EventEmitter();

  // Emit later on
  process.nextTick(() => {
    ee.emit('foo', 'bar');
    ee.emit('foo', 42);
  });

  for await (const event of on(ee, 'foo')) {
    // The execution of this inner block is synchronous and it
    // processes one event at a time (even with await). Do not use
    // if concurrent execution is required.
    console.log(event); // prints ['bar'] [42]
  }
  // Unreachable here
})();

Returns an AsyncIterator that iterates eventName events. It will throw if the EventEmitter emits 'error'. It removes all listeners when exiting the loop. The value returned by each iteration is an array composed of the emitted event arguments.

An AbortSignal can be used to cancel waiting on events:

const { on, EventEmitter } = require('events');
const ac = new AbortController();

(async () => {
  const ee = new EventEmitter();

  // Emit later on
  process.nextTick(() => {
    ee.emit('foo', 'bar');
    ee.emit('foo', 42);
  });

  for await (const event of on(ee, 'foo', { signal: ac.signal })) {
    // The execution of this inner block is synchronous and it
    // processes one event at a time (even with await). Do not use
    // if concurrent execution is required.
    console.log(event); // prints ['bar'] [42]
  }
  // Unreachable here
})();

process.nextTick(() => ac.abort());

Since

v13.6.0, v12.16.0

Parameters​

NameTypeDescription
emitterEventEmitter-
eventNamestringThe name of the event being listened for
options?StaticEventEmitterOptions-

Returns​

AsyncIterableIterator<any>

that iterates eventName events emitted by the emitter

Inherited from​

EventEmitter.on

Defined in​

node_modules/@types/node/events.d.ts:254

once​

▸ Static once(emitter, eventName, options?): Promise<any[]>

Creates a Promise that is fulfilled when the EventEmitter emits the given event or that is rejected if the EventEmitter emits 'error' while waiting. The Promise will resolve with an array of all the arguments emitted to the given event.

This method is intentionally generic and works with the web platform EventTarget interface, which has no special'error' event semantics and does not listen to the 'error' event.

const { once, EventEmitter } = require('events');

async function run() {
  const ee = new EventEmitter();

  process.nextTick(() => {
    ee.emit('myevent', 42);
  });

  const [value] = await once(ee, 'myevent');
  console.log(value);

  const err = new Error('kaboom');
  process.nextTick(() => {
    ee.emit('error', err);
  });

  try {
    await once(ee, 'myevent');
  } catch (err) {
    console.log('error happened', err);
  }
}

run();

The special handling of the 'error' event is only used when events.once()is used to wait for another event. If events.once() is used to wait for the 'error' event itself, then it is treated as any other kind of event without special handling:

const { EventEmitter, once } = require('events');

const ee = new EventEmitter();

once(ee, 'error')
  .then(([err]) => console.log('ok', err.message))
  .catch((err) => console.log('error', err.message));

ee.emit('error', new Error('boom'));

// Prints: ok boom

An AbortSignal can be used to cancel waiting for the event:

const { EventEmitter, once } = require('events');

const ee = new EventEmitter();
const ac = new AbortController();

async function foo(emitter, event, signal) {
  try {
    await once(emitter, event, { signal });
    console.log('event emitted!');
  } catch (error) {
    if (error.name === 'AbortError') {
      console.error('Waiting for the event was canceled!');
    } else {
      console.error('There was an error', error.message);
    }
  }
}

foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!

Since

v11.13.0, v10.16.0

Parameters​

NameType
emitter_NodeEventTarget
eventNamestring | symbol
options?StaticEventEmitterOptions

Returns​

Promise<any[]>

Inherited from​

EventEmitter.once

Defined in​

node_modules/@types/node/events.d.ts:194

▸ Static once(emitter, eventName, options?): Promise<any[]>

Parameters​

NameType
emitter_DOMEventTarget
eventNamestring
options?StaticEventEmitterOptions

Returns​

Promise<any[]>

Inherited from​

EventEmitter.once

Defined in​

node_modules/@types/node/events.d.ts:195

setMaxListeners​

▸ Static setMaxListeners(n?, ...eventTargets): void

const {
  setMaxListeners,
  EventEmitter
} = require('events');

const target = new EventTarget();
const emitter = new EventEmitter();

setMaxListeners(5, target, emitter);

Since

v15.4.0

Parameters​

NameTypeDescription
n?numberA non-negative number. The maximum number of listeners per EventTarget event.
...eventTargets(EventEmitter | _DOMEventTarget)[]-

Returns​

void

Inherited from​

EventEmitter.setMaxListeners

Defined in​

node_modules/@types/node/events.d.ts:346