Is there a way I can loop inside a var in typescript?

Question

setup() {
    var nodes = {
      node1: { name: "Node 1" },
      node2: { name: "Node 2" },
      node3: { name: "Node 3" },
      node4: { name: "Node 4" },
    }
    var edges = {
      edge1: { source: "node1", target: "node2" },
      edge2: { source: "node2", target: "node3" },
      edge3: { source: "node3", target: "node4" },
    }
    return { nodes, edges }
  }

So instead of writing node1,node2, and so on, is there a way I can loop and create the exact same thing? Any suggestions are appreciated.

Answer 1

Yes. You can dynamically create property names using something like Object.fromEntries.

Object.fromEntries creates an object from a series of entries, where an "entry" is an array with two elements: a property name, and a value for that property.

Here's an example that recreates your data above:

function setup() {
    const nodes = Object.fromEntries(
      [1,2,3,4].map(n => ["node"+n, { name: "Node " + n }])
    )
    const edges = Object.fromEntries(
      [1,2,3].map(n => [
        "edge"+n, 
        { source: "node" + n, target: "node" + String(n+1) }
      ])
    )
    return { nodes, edges }
 }
 console.log(setup())

Answer 2

Sure you can! Many ways, one of the common ones is:

const nodes = Object.fromEntries(
  Array.from(Array(10).keys())
    .map(i => [`node${i + 1}`, {name: `Node ${i + 1}`}])
);

/* nodes are:
{
    "node1": {
        "name": "Node 1"
    },
    "node2": {
        "name": "Node 2"
    },
    "node3": {
        "name": "Node 3"
    },
    "node4": {
        "name": "Node 4"
    },
    "node5": {
        "name": "Node 5"
    },
    "node6": {
        "name": "Node 6"
    },
    "node7": {
        "name": "Node 7"
    },
    "node8": {
        "name": "Node 8"
    },
    "node9": {
        "name": "Node 9"
    },
    "node10": {
        "name": "Node 10"
    }
}
*/

Answer 3

The following code has the same result but uses for-loops, please be more specific in your question if you need something else.

setup() {
    var nNodes = 4
    var nEdges = 3
    var nodes = {}
    var edges = {}

    for(i = 1 ; i < nNodes + 1; i++){
        nodes['node'+i.toString()] = {"name": "Node " + i.toString()}
    }
    for(i = 1 ; i <nEdges + 1; i++){
        edges['edge'+(i+1).toString()] = {"source": "node"+i.toString(), "target": "node"+(i+1).toString()}
    }
    return { nodes, edges }
  }

Answer 4

Try this (I just added a logic to generate the objects) :

const nodes = {}
var edges = {}

for (let i = 1; i <= 4; i++) {
  nodes['node' + i] = { name: 'Node ' + i }
  if (i !== 4) {
    edges['edge' + i] = { source: 'node' + i, target: 'node' + (i + 1)
    }
  }
}

console.log(nodes);
console.log(edges);

Answer 5

Need to loop through and append them:

foreach (range(1, 12) as $number){
  $numbers[] = sprintf("%03d", $number);
}

print_r($numbers);