迭代原始数组，在每次迭代中创建一个新对象，为它添加一个.id，然后迭代元素以获得其余的键值对：

function convert2(arrayOfObjects) {
  const newObjects = [];
  
  for (const [index, keyValuePairs] of arrayOfObjects.entries()) {
    const object = {};
    
    object.id = index + 1;
    
    for (const { prop1: key, prop2: value } of keyValuePairs) {
      object[key] = value;
    }
    
    newObjects.push(object);
  }
  
  return newObjects;
}

试试看（精简版）：

function convert(arrayOfObjects) {
  return arrayOfObjects.map(
    (keyValuePairs, index) => Object.fromEntries(
      keyValuePairs.map(
        ({ prop1: key, prop2: value }) => [key, value]
      ).concat([
        ['id', index + 1]
      ])
    )
  );
}

const test = [
  [{ prop1: 'FieldName', prop2: 'FieldValue' }],
  [
    { prop1: 'OtherFieldName', prop2: 'OtherFieldValue' },
    { prop1: 'AnotherFieldName', prop2: 'AnotherFieldValue' }
  ],
];

console.log(convert(test));

.as-console-wrapper {
  max-height: 100% !important;
}

这里有一个解决方案。

const input = [
  [{
    prop1: 'FieldName',
    prop2: 'FieldValue'
  }],

  [{
    prop1: 'OtherFieldName',
    prop2: 'OtherFieldValue'
  }],
]

const output = [];
for (const arr of input) {
  for (let i = 0; i < arr.length; i++) {
    const item = arr[i];
    output.push({
      id: output.length + 1,
      [item.prop1]: item.prop2
    })
  }
}
console.log(output);