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const roads = ["Alice's House-Bob's House", "Alice's House-Cabin", "Alice's House-Post Office"]; 

function buildGraph(edges) {
    let graph = Object.create(null);
    function addEdge(from, to) {
        if (graph[from] == null) {
            graph[from] = [];
        }
        graph[from].push(to);    
    }
    for (let [from, to] of edges.map(r => r.split("-"))) {
        addEdge(from, to);
        addEdge(to, from);
    }
    return graph;
}

const roadGraph = buildGraph(roads);
console.log(roadGraph);

//roadGraph object:
[Object: null prototype] {
"Alice's House": [ "Bob's House", 'Cabin', 'Post Office' ],
"Bob's House": [ "Alice's House" ],
Cabin: [ "Alice's House" ],
'Post Office': [ "Alice's House" ]
}

Why do we have such inconsistencies?

  • Cabin and Post Office values in Alice's House are in single quotes
  • the Cabin key has no quotes
  • Post Office key has single quotes
user13140823
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  • You're seeing the browser debugger showing you your object in the simplest way it thinks it can. It makes absolutely no difference how a string appears quoted; the quotes aren't part of the string value anyway. – Pointy Mar 28 '20 at 13:43
  • You shouldn't pay attention to this. It's just how your console chooses to represent things - it's not reflective of what you actually have as content, since string *content* doesn't have surrounding quotes. The console only puts them there to make it more clear it's a single string. And it likely swaps between single and double quotes because the string already contains a single quote, so it just puts doubles around it to be clear where it starts and ends. – VLAZ Mar 28 '20 at 13:43
  • `{cabin: 1}` or `{"cabin": 1}` or `{'cabin': 1}` or `{\`cabin\`: 1}` ..... it does not matter – epascarello Mar 28 '20 at 13:45
  • https://stackoverflow.com/questions/4348478/what-is-the-difference-between-object-keys-with-quotes-and-without-quotes – epascarello Mar 28 '20 at 13:47
  • Browser debugger output shows a json property double quoted if property name contains spaces. – Berk Öztürk Mar 28 '20 at 13:56

1 Answers1

2

In JavaScript, single and double quotes are interchangeable. You can use whichever you prefer.

Double quotes are often preferred when the string contains single quotes, as it reduces the amount of escaping:

"Alice's House"
'Alice\'s House'

It would appear that the console prefers single quotes, but switches to double quotes when the string contains an apostrophe (single quote).

In general, some prefer to choose a single style and stick to it, but there is no requirement to do so, so it's up to the developer or team. However, for auto-generated code, there is no need to be concerned.

JDB
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  • This is not about *what to use* but *why it's shown*. – VLAZ Mar 28 '20 at 13:44
  • @VLAZ They explained this, "as it reduces the amount of escaping". – Mr. Polywhirl Mar 28 '20 at 13:45
  • @Mr.Polywhirl but the quotes are *irrelevant*. "Which quotes to use" is NOT an appropriate answer as it refers to string literals. If you're seeing them in the console, that's *not* a string literal and *not* something that *you* use. In fact, there is nothing stopping the console using `|` or `` as delimiters of strings. – VLAZ Mar 28 '20 at 13:48
  • @vlaz updated. I feel the meat of my answer was still correct, but I missed that the content at the bottom was generated by the console. – JDB Mar 28 '20 at 13:50