SyntaxError Unexpected token if within a function

Question

I'm currently learning javascript (by using Google Script currently), I feel like this is a simple mistake, but I can't figure out a way around it.

The code below works, if I set "var colour" to a colour code. But when I change it to an if statement I get the issue. I've tried a bunch of different formats and continued having the same issue...

For info it just gets a few rows from a spreadsheet and then formats the selected rows and displays it to the user.

//Example of part of working code:
  if(Line.length == 0){
  var Line = lines 
  .slice(1)
  .filter(function(row) { return row[4] == e.message.text;})
  .map(function(row) {
    var colour = if(row[6]=1){return "#ff0000"};
    return '<b>' + row[3] + '</b> ('+ row[1] + ' or ' +row[2] + ')' + '\n' + '<font color=' + colour + '>Region: ' + row[6] + "</font>";
  });
  } 

Answer 1

There is a difference between statements and expressions.

Just like you can put apples in a basket but not baskets in an apple, you can put expressions in a statement but not a statement in expressions.

var colour = ... is a statement that expects an expression on the right-hand side of the equals sign. You can't put an if statement there. You can use a conditional operator to make a a conditional expression:

var colour = row[6] == 1 ? "#ff0000" : "#000000";

Or you can use a full if statement to execute two variant assignment statements:

var colour;
if (row[6] == 1) {
  colour = "#ff0000";
} else {
  colour = "#000000";
}

Note also that return #ff0000 would have returned literally "#ff0000", not the text with the colour #ff0000 as I assume you want; also note that row[6] = 1 would assign 1 to row[6], not compare it.