Merge property lists across pages

How to?
#1

I need to convert a set of records (one record per page) into a single table. Each record is formatted as a list of name:value pairs but not every record has every field, i.e. some records are missing some data points.

As an example, I've picked the best sellers list on amazon:

URL: https://www.amazon.co.uk/gp/bestsellers/books/

Sitemap:
{"_id":"amzbestsellers","startUrl":["https://www.amazon.co.uk/gp/bestsellers/books/"],"selectors":[{"id":"book","type":"SelectorLink","parentSelectors":["_root"],"selector":".zg-item > a","multiple":true,"delay":0},{"id":"details","type":"SelectorText","parentSelectors":["_root"],"selector":".a-section #detailBullets_feature_div ul","multiple":false,"regex":"","delay":0},{"id":"data","type":"SelectorText","parentSelectors":["book"],"selector":".a-section #detailBullets_feature_div ul","multiple":false,"regex":"","delay":0}]}

#2

Try this:

{"_id":"amazon-uk-bestsellers-paginate","startUrl":["https://www.amazon.co.uk/gp/bestsellers/books/"],"selectors":[{"id":"Item wrappers","type":"SelectorElement","parentSelectors":["_root","Next page"],"selector":"ol li div.aok-relative","multiple":true },{"id":"Next page","type":"SelectorElementClick","parentSelectors":["_root"],"selector":"div > ol[id*='ordered-list']","multiple":false,"delay":"4500","clickElementSelector":"ul.a-pagination li.a-last a","clickType":"clickMore","discardInitialElements":"discard","clickElementUniquenessType":"uniqueHTML"},{"id":"Title","type":"SelectorText","parentSelectors":["Item wrappers"],"selector":"a.a-link-normal div[title],a.a-link-normal div[aria-hidden][data-rows]","multiple":false,"regex":"" },{"id":"Link","type":"SelectorLink","parentSelectors":["Item wrappers"],"selector":"span > a.a-link-normal","multiple":false },{"id":"Author","type":"SelectorText","parentSelectors":["Item wrappers"],"selector":"div[class^='a-row'] > a.a-link-child,span[class^='aok-inline-block'] > div:nth-of-type(1) span","multiple":false,"regex":"" },{"id":"Position","type":"SelectorText","parentSelectors":["Item wrappers"],"selector":"span.zg-badge-text","multiple":false,"regex":"(?<=#)\\d+" }]}