Crash on IE11

[oliviertassinari]

Intended outcome:

No error.

Actual outcome:

Unable to get property 'get' of undefined or null reference

How to reproduce the issue:

Go to IE 11 and run:

function getOrCreate(value) {
  var map = new Map();
  return map.get(value) || map.set(value, 'foo').get(value);
}

getOrCreate(undefined)

from:

apollo-client/packages/apollo-cache-inmemory/src/optimism.ts

Lines 42 to 45 in 51aee1f

	getOrCreate(value: any): CacheKeyNode<KeyType> {
	const map = this.children || (this.children = new Map);
	return map.get(value) || map.set(value, new CacheKeyNode<KeyType>()).get(value);
	}

Versions

apollo-cache-inmemory@^1.3.5:
  version "1.3.5"
  resolved "https://registry.yarnpkg.com/apollo-cache-inmemory/-/apollo-cache-inmemory-1.3.5.tgz#7628ee598271cfffa611e15a7ce67652a84b07b0"
  dependencies:
    apollo-cache "^1.1.17"
    apollo-utilities "^1.0.21"
    optimism "^0.6.6"

[oliviertassinari]

Even better:

new Map().set('foo', 'bar')

returns undefined on IE 11 when it returns itself on the latest implementations.

[oliviertassinari]

The following implementation works:

    CacheKeyNode.prototype.getOrCreate = function (value) {
        var map = this.children || (this.children = new Map);
        var output = map.get(value)
        if (output) {
            return output
        }
        output = new CacheKeyNode()
        map.set(value, output)
        return output
    };

[oliviertassinari]

Same report here: vercel/next.js#5426.

[oliviertassinari]

According to @barnslig, it's a regression, it used to work in v1.2.10.

[benjamn]

This should be fixed with apollo-cache-inmemory@1.3.7 (just published).

[oliviertassinari]

Thank you!