JSON as a JavaScript Object
Consider a converter stack in a step that contains a Convert Using JavaScript converter. This converter gets access to the output from the previous converter as a variable named INPUT to use in the JavaScript used by the converter. The value of the INPUT variable is always a String.
The following table shows possible conversion values for the INPUT variable.
|
INPUT Value |
JavaScript (OUTPUT =) |
Result (OUTPUT value) |
|---|---|---|
|
5 |
OUTPUT = INPUT |
5 |
|
5 |
OUTPUT = INPUT + 3 |
53 |
|
5 |
OUTPUT = eval(INPUT) |
5 |
|
5 |
OUTPUT = eval(INPUT) + 3 |
8 |
|
5 |
OUTPUT = eval(INPUT + 3) |
53 |
|
5 |
OUTPUT = eval(INPUT + " + 3") |
8 |
|
[1,2,3] |
OUTPUT = INPUT[0] |
[ |
|
[1,2,3] |
OUTPUT = eval(INPUT)[0] |
1 |
|
{ “a”: 5 } |
OUTPUT = eval(INPUT).a |
“Syntax Error” |
|
{ “a”: 5 } |
OUTPUT = eval("var x=" + INPUT + "; x;").a; |
5 |
Note the following when converting JSON to JavaScript:
- INPUT is a variable bound to a string value. Therefore, any operation that you perform on INPUT is a string operation. For example, + is string concatenation. That is why INPUT + 3 becomes 53 in the example above.
- The function "eval" only accepts correct JavaScript as input and {"a":5} is not a syntactically correct JavaScript line, but var x = {"a":5} is, which is why the last example above is the one that works.