Is there a name for this JSON formatting pattern, with leading commas?

Question

I have seen valid JSON written this way: { "version": 1 , "object": { "one": 1 , "two": 2 , "three": 3 , "four": 4, , "five": 5 } , "array": [ 1 , 2 , 3 ] , "people": [ { "firstname": "Jacob", , "lastname": "Ford" } , { "firstname": "Marcin" , "lastname": "Wichary" } ] } My guess as to the the primary advantage is that the addition or removal of one line of data will (with a few exceptions) be diff'd as just that: a single-line addition or deletion. As opposed the more typical JSON presentation, with trailing commas, where appending an item to the end of an array or object requires editing the line before it, to add a comma. Is there a name for this JSON presentation convention, with leading commas, and commas placed in same column as opening/closing brackets? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

It appears to generally be referred to as comma-first notation (though is sometimes also called leading comma notation), and can apply to more than just JSON. SQL commands are another good example. npm's code style guide requires it for all comma-separated lists. Airbnb's forbids it. My assumption about this style producing cleaner diffs was correct; however some prefer to achieve the same goal by sticking with trailing commas, but always including an (unnecessary) dangling comma after the final item. The aforementioned Airbnb code style guide, in the section immediately after forbidding comma-first notation, requires dangling commas after lists, explicitly for cleaner diffs. There is one additional advantage proponents point to, which is that typographical errors become much more apparent in comma-first notation. This gist by the inventor of npm is often cited, which I'll excerpt here: // error in standard style var a = "ape", b = "bat", c = "cat", d = "dog" e = "elf", f = "fly", g = "gnu", h = "hat", i = "ibu"; // error in comma-first style var a = "ape" , b = "bat" , c = "cat" , d = "dog" e = "elf" , f = "fly" , g = "gnu" , h = "hat" , i = "ibu" ;