JS 对象的数组值和键中的引号不一致

Question

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

Answer 1

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.