Sending client a NodeJS object with some undefined property values-CodePudding

I'm running a PostgreSQL query:

'SELECT * FROM table'

On my server side, I'm trying to generate a JSON object of the below format, but some of the column# values are set to 'undefined' because the row.value# is undefined:

{
  column1: row.value1,
  column2: row.value2,
  column3: row.value3,
  column4: row.value4,
  column5: row.value5,
  column6: row.value6,
  column7: row.value7,
  column8: row.value8,
  column9: row.value9,
}

On my client side, I'm trying to receive a set of JSON objects, but they don't have the same format because whenever one of the column#'s has a value of undefined, it's removed from the JSON object so that it looks like the below (because column5, column6, and column8 were undefined).

{
  column1: row.value1,
  column2: row.value2,
  column3: row.value3,
  column4: row.value4,
  column7: row.value7,
  column9: row.value9,
}

My solution was to give the properties in the JSON object a default value in case of the row.value# being undefined. How can I do this (replace 'undefined' with some default value in the object).

CodePudding user response：

You can use a ternary operator (? :) like this:

const row = {
  value2: "Praveen",
  value6: "Kumar",
  value8: "Purushothaman"
};

console.log({
  column1: row.value1 ? row.value1 : "NA",
  column2: row.value2 ? row.value2 : "NA",
  column3: row.value3 ? row.value3 : "NA",
  column4: row.value4 ? row.value4 : "NA",
  column5: row.value5 ? row.value5 : "NA",
  column6: row.value6 ? row.value6 : "NA",
  column7: row.value7 ? row.value7 : "NA",
  column8: row.value8 ? row.value8 : "NA",
  column9: row.value9 ? row.value9 : "NA",
});

This gives me an output of:

{
  "column1": "NA",
  "column2": "Praveen",
  "column3": "NA",
  "column4": "NA",
  "column5": "NA",
  "column6": "Kumar",
  "column7": "NA",
  "column8": "Purushothaman",
  "column9": "NA"
}

There is a way to use null coalescing operator too. But that might not be supported always. However, the above logic works every time.

CodePudding user response：

You can do something like this

const defaultValues = {
  col1: "col1",
  col2: "col2",
  col3: "col3"
};

const fromApi = {
col2 : 'my value col2'
}


const result = {...defaultValues, ...fromApi}

console.log(result)