transcontextual safe type checks

[axkibe]

In case the supplied function goes into a different context (using vm.SourceTextModule for example) the "instanceof" checks fail.

typeof obj === 'function' and Array.isArray are true among contexts.

BTW: as far I read isArray has explicitly been created for cross-realm situations.

[jsumners]

This change makes sense. Using instanceof is rarely a good idea. How can we add a unit test to guard against regression?

[axkibe]

An extremely simplified minimal example of what I was doing. Also switched to vm.runInContext since vm.SourceTextModule is still behind an experimental flag:

const ldap = require('ldapjs');
const vm = require('node:vm');
const ctx = vm.createContext({});
vm.runInContext(`
globalThis.search=function(){};
globalThis.searches=[function(){}];
`, ctx);
const server = ldap.createServer();
server.search('', ctx.search);
server.search('', ctx.searches);

This will fail with instanceof but work with typeof and isArray.

[jsumners]

Can you please add a unit, or integration, test that will fail without this change?

[axkibe]

Ok, done.

[jsumners]

Looks good to me.

[jsumners]

https://github.com/ldapjs/node-ldapjs/releases/tag/v3.0.2