如何在异步函数中访问双嵌套数组中的数据 - javascript？

getBlock是异步的，因此您正在解析一个空数组，因为forjavascript 中的循环是同步的，但是您在其中使用了异步回调，并且在is之前被resolve调用。 tx.push

我建议您采用递归异步方法，如下所示：

function getBlockchainTransactions(blockNumber){
    var tx = [];
    return new Promise(resolve => {
            // declare a recrusive async loop.
         var recursiveAsyncLoop = function(current, max) {
            // If the current index is exactly blockNumber, resolve.
          if (current === max) {
            resolve(tx);
          }
          // Otherwise, excute the operation on the actual block.
          else {
            var i = current;
            web3.eth.getBlock(i, function(error, block){
              if(!error && block.transactions.length != 0){
                console.log(block.transactions);
                tx.push(block.transactions);
                // once the operation is finished, increase the counter on the next call.
                recursiveAsyncLoop(current + 1, max);
              }
              // In cany case, regardless the above is true or false, continue.
              else recursiveAsyncLoop(current + 1, max);
            })
          }
         }
         // Begin the loop, from index 0 until blockNumber (excluded).
         recursiveAsyncLoop(0, blockNumber);
    });

}


async function msg() {
    const transakcije = await getBlockchainTransactions(blockNumber);
    console.log(transakcije);
}

resolve仅当项目有效地添加到数组时才应调用上述代码。