PHP json_encode with Boolean and decimal values

Question

I have a PHP function that takes data from the database and returns an array with the results. This array by default has all the data as type string, but some fields should be treated as Boolean while others should be treated as values (money) and are of the type decimal.

Later I make use of this data in the HTML page to perform some functions or display data. For example:

• valor - type _decimal(10,2) - Used to display the value of a product.
• ativo - tinyint type - Used to mark or not a checkbox.

The array of data I obtain is generated through a query (SELECT) to the database, with this the return comes with all fields in string. This "solves" a part of the problem as it keeps the field valor with the decimal places. The problem starts when I try the conversion, using flags in the json_encode, turn the values back to Boolean (or int), and then I have these two cases:

Case 1: When I use json_encode($resposta,JSON_NUMERIC_CHECK) the column valor loses its decimals and is rounded. Ex: 9.90(string) -> 10(int)

Case 2: When I use json_encode($resposta,JSON_PRESERVE_ZERO_FRACTION ) the column ativo comes as string and I can’t control the checkbox.

Is there any way around this situation?

Answer 1

Bringing here the code I have written in the comments. A simpler solution than trying to coordinate the flags json_encode() is to treat values before moving to function.

In that case, if ativo must be a intor bool and valor should be a string, only need to treat the asset and no flag is required, since in the output of your SQL all values come as string:

$produtos = array(
    array(
        'valor'=> "1.95",
        'ativo'=> '1'
    ),
    array(
        'valor' => '9.90',
        'ativo' => '0'
    ),
);

foreach( $produtos as $produto ) {
    $produto['ativo'] = abs($produto['ativo']);
    $resposta[] = $produto;
}

echo json_encode( $resposta );

Upshot:

[{"valor":"1.95","ativo":1},{"valor":"9.90","ativo":0}]

If you needed to convert a value to string you could also use 'valor' => (string) 1.95 for example.

Answer 2

I did a test to demonstrate that there is no difficulty with decimals or booleans when converting to json format.

<?php

$x = array(9.9, 0);

$j = json_encode($x);
?>
<script>
v = JSON.parse('<?php echo $j;?>');
//document.write(v[0]);

if (v[1]) {
    s = 'verdadeiro';
} else {
    s = 'falso';
}

document.write(s);
</script>

Your question does not make clear where and how does the comparisons of boolean values, but by the comments seems to be with Javascript.

For Javascript the value 1 is true and value 0 is false when they are numeric values. If it is a string type v = '0', for example, v will be taken as true.

To "dribble" this can solve with the function parseInt().

<?php

$x = array(9.9, '0');

$j = json_encode($x);
?>
<script>
v = JSON.parse('<?php echo $j;?>');
//document.write(v[0]);

if (parseInt(v[1])) {
    s = 'verdadeiro';
} else {
    s = 'falso';
}

document.write(s);
</script>

As for the decimal value, it can come as a database string that will make no difference.

However, to provide consistency with mathematical operations in Javascript, convert with the function parseFloat() when you need to do mathematical operations.

a = '9.9';
b = 3;
document.write(parseFloat(a) + b);

Just out of curiosity, for PHP it is similar. Just rename the functions. It would be intval() and floatval().

And of course, I disregarded the comparison that checks the type of variable. if (v === true) {, for example, you need another more suitable treatment. But the important thing is that you do not need to touch anything in the json_encode() for both cases.