遍历 arrays 个对象的数组

Question

I have an array of arrays of objects that I want to loop over and print each element but for some reason, the loop is skipping some elements, and I understand why but I don't know what is the best way to fix it

Here is the code I used:

const test = [
  [
    {
      SESSION_ID: "200",
    },
    {
      SESSION_ID: "296",
    },
  ],
  [
    {
      MICROFILM_REF_NUMBER: "9,52E+22",
    },
    {
      MICROFILM_REF_NUMBER: "9,52E+22",
    },
  ],
];

test.forEach((element, index) => {
  console.log(element[index].SESSION_ID);
  console.log(element[index].MICROFILM_REF_NUMBER);
});

The output I get is:

200
undefined
undefined
9,52E+22

The desired output is:

200
296
9,52E+22
9,52E+22 

Answer 1

You should probably use different data structure but for your question, this is one of answers

test.forEach((array, index) => {
  array.forEach((element, idx)=>{
    if(element.SESSION_ID) console.log(element.SESSION_ID)
    if(element.MICROFILM_REF_NUMBER) console.log(element.MICROFILM_REF_NUMBER)
  })
});

Answer 2

I have an array of arrays of objects that I want to loop over and print each element but for some reason, the loop is skipping some elements, and I understand why but I don't know what is the best way to fix it

Here is the code I used:

const test = [
  [
    {
      SESSION_ID: "200",
    },
    {
      SESSION_ID: "296",
    },
  ],
  [
    {
      MICROFILM_REF_NUMBER: "9,52E+22",
    },
    {
      MICROFILM_REF_NUMBER: "9,52E+22",
    },
  ],
];

test.forEach((element, index) => {
  console.log(element[index].SESSION_ID);
  console.log(element[index].MICROFILM_REF_NUMBER);
});

The output I get is:

200
undefined
undefined
9,52E+22

The desired output is:

200
296
9,52E+22
9,52E+22 

Answer 3

Since you mentioned a table I believe you want something more along the lines of the following that maps your data to a rows array that can then easily be iterated to insert rows and cells into a table element

 const col_props = ['SESSION_ID', 'MICROFILM_REF_NUMBER']; const rows = data[0].map((_, i) => { return data.map((arr, j) => arr[i][col_props[j]]); }); console.log('Rows:',JSON.stringify(rows)) // for headings in demo rows.unshift(col_props) const table = document.querySelector('#myTable'); rows.forEach(arr => { const row = table.insertRow() arr.forEach(v => row.insertCell().textContent = v) })

 <table id="myTable" border="1"></table> <script> const data=[[{SESSION_ID:"200"},{SESSION_ID:"296"}],[{MICROFILM_REF_NUMBER:"9,52E+22"},{MICROFILM_REF_NUMBER:"9,52E+22"}]]; </script>