How BitcoinJS sync bitcoin blockchain/transaction data?

How BitcoinJS sync bitcoin blockchain/transaction data?

I see the reference code in BitcoinJS website about 'Creating a Transaction':

var tx = new bitcoin.TransactionBuilder()

// Add the input (who is paying):
// [previous transaction hash, index of the output to use]
var txId = 'aa94ab02c182214f090e99a0d57021caffd0f195a81c24602b1028b130b63e31'
tx.addInput(txId, 0)

My question is how it get the data about tx(like its inputs/outputs)? Does it link to some nodes or API like blockchain.info?

http://ift.tt/2AhtbGN

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