function countSpaces(tokens) {
			const before = tokens.arrow.range[0] - tokens.before.range[1];
			const after = tokens.after.range[0] - tokens.arrow.range[1];

			return { before, after };
		}
Count spaces before/after arrow(`=>`) token.
@param {Object} tokens Tokens before/after arrow.
@returns {Object} count of space before/after arrow.