NodeJS SyntaxError: Unexpected token '.'-CodePudding

Beginner to Node JS and NPM. The following code throws a Syntax error and can't figure out the issue.

Node version: v12.18.3 NPM version: 7.15.1

Error

LayerObj.options?.["displayName"] != undefined
                       ^

SyntaxError: Unexpected token '.'
    at wrapSafe (internal/modules/cjs/loader.js:1053:16)
    at Module._compile (internal/modules/cjs/loader.js:1101:27)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1157:10)
    at Module.load (internal/modules/cjs/loader.js:985:32)
    at Function.Module._load (internal/modules/cjs/loader.js:878:14)
    at Module.require (internal/modules/cjs/loader.js:1025:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at Object.<anonymous> (/Applications/MAMP/htdocs/nft-generators/hashlips_art_engine-main/index.js:2:39)
    at Module._compile (internal/modules/cjs/loader.js:1137:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1157:10)

Code

const layersSetup = (layersOrder) => {
  const layers = layersOrder.map((layerObj, index) => ({
    id: index,
    elements: getElements(`${layersDir}/${layerObj.name}/`),
    name:
      layerObj.options?.["displayName"] != undefined
        ? layerObj.options?.["displayName"]
        : layerObj.name,
    blend:
      layerObj.options?.["blend"] != undefined
        ? layerObj.options?.["blend"]
        : "source-over",
    opacity:
      layerObj.options?.["opacity"] != undefined
        ? layerObj.options?.["opacity"]
        : 1,
    bypassDNA:
      layerObj.options?.["bypassDNA"] !== undefined
        ? layerObj.options?.["bypassDNA"]
        : false,
  }));
  return layers;
};

CodePudding user response：

Optional chaining (?.) was added in Node.js 14 and is not directly available in Node 12.

The ?. operator is like the . chaining operator, except that instead of causing an error if a reference is nullish (null or undefined), the expression short-circuits with a return value of undefined. When used with function calls, it returns undefined if the given function does not exist.

Use a more recent version of Node or use Node 12 compatible code.

New JS features in Node.js v14.0 discusses some new language constructs in Node 14.