Parse a JSON from a webhook that is catched by Zapier

I need to parse the information that is being send to Zapier using JavaScript so that the names actually fits with the values. There is a tutorial in this link: https://community.zapier.com/featured-articles-65/how-to-parse-json-style-key-value-pair-arrays-into-zapier-mappable-values-7493 But it did not worked for me so I need someone who understand JavaScript better.