René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Question: Why does \"this\" not have a type in function assigned to class prototype ","articleBody":"**TypeScript Version:** \n\n1.8.9\n\n**Code**\n\n``` configuration.ts\nexport class Configuration {\n    private storage: string;\n\n    constructor() {\n        this.storage = \"InMemoryStorageProvider()\";\n    }\n\n    public useLocalStorage(): void {\n        // This method will be injected via the prototype.\n    }    \n}\n```\n\n``` prototypetest.ts\nimport { Configuration } from './classes/Configuration';\n\nConfiguration.prototype.useLocalStorage = function() {\n    this.storage = \"NodeFileStorageProvider\"\n};\n```\n\n**Expected behavior:**\n\nWhen walking the AST I use:\n\n```\nlet identifier: ts.Identifier = \u003cts.Identifier\u003enode;\nlet identifierSymbol: ts.Symbol = this.checker.getSymbolAtLocation( identifier );\n```\n\nto obtain the identifier and its possible associated symbol when the node is SyntaxKind.Identifier.\n\nfor the first 2 references to the private property `storage`, I obtain the identifier and the symbol (which correctly have the same `Id`). With the prototype function assigned to useLocalStorage the reference to `storage` the call to `this.checker.getSymbolAtLocation( identifier )` does not return a symbol.\n\n**Actual behavior:** \n\nI am using the AST to identify identifiers which may be minified/shortened. The 1st and 2nd reference to `storage` gets shortened as it is a private property.\n\nMy expectation was that the reference to `storage` would have the same symbol ( not undefined ) as the other references to the `storage` property. \n","author":{"url":"https://github.com/ToddThomson","@type":"Person","name":"ToddThomson"},"datePublished":"2016-04-12T14:57:24.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/8024/TypeScript/issues/8024"}