var arr = [ [ 'cardType', 'iDEBIT' ],
  [ 'txnAmount', '17.64' ],
  [ 'txnId', '20181' ],
  [ 'txnType', 'Purchase' ],
  [ 'txnDate', '2015/08/13 21:50:04' ],
  [ 'respCode', '0' ],
  [ 'isoCode', '0' ],
  [ 'authCode', '' ],
  [ 'acquirerInvoice', '0' ],
  [ 'message', '' ],
  [ 'isComplete', 'true' ],
  [ 'isTimeout', 'false' ] ]

var obj = Object.assign(...arr.map(([key, val]) => ({[key]: val})))

console.log(obj)

/*
acquirerInvoice: "0"
authCode: ""
cardType: "iDEBIT"
isComplete: "true"
isTimeout: "false"
isoCode: "0"
message: ""
respCode: "0"
txnAmount: "17.64"
txnDate: "2015/08/13 21:50:04"
txnId: "20181"
txnType: "Purchase"
*/