Description:
In my Javascript code I have a logical expression as a string, like in the example below:
'foo && !bar || baz'
Where foo, bar and baz are the names of some tags within my app.
A tag can contain lowercase, uppercase letters, numbers and special characters (+, - , *, #, etc). So the following strings may be valid tags:
foo-bar, foo#, f*oo.
The possible logical operators are: || (OR), && (AND) and ! (NOT).
Requirement:
I need to get only the tags from the string above, as an array:
['foo', 'bar', 'baz']
The code I've tried:
I tried to use the regex /&&|\|/ to get the logical operators, and then try to invert the logical expression, but without success.
Other examples:
foo && bar => expected result ['foo', 'bar']
foo1 || bar1 => expected result ['foo1', 'bar1']
foo+ && !bar& => expected result ['foo+', 'bar&']
foo && bar || baz => expected result ['foo', 'bar', 'baz']
You can simply split on the operators:
var text = 'foo && bar& || !baz';
var regex = / *(?:&&|\|\||!) */;
var tags = text
.split(regex) // split on operators
.filter(Boolean); // filter out empty items
console.log('text: ' + text);
console.log('tags: ' + JSON.stringify(tags));Output:
text: foo && bar& || !baz
tags: ["foo","bar&","baz"]
This test input covers the corner case of consecutive operators (|| and !), and a single & as part of the tag name.
Explanation of regex used for split:
* - expect optional space(?:&&|\|\||!) -followed by all ORed operators; (?:...) is a non-capturing group (split includes captured groups in the resulting array) * - followed by optional spaces