typescript, ts-morph, resolving parameter type in `export function fn_record(a: Record

The code being compiled and processed is:

export function fn_record(a: Record<string, any>): void {}  

The node tree after compilation is shown below under File node tree.

What I want to do is use ts-morph module to produce somewhere a structure equivalent (up to arbitrary names) to that produced by :

export function fn_index(a: {[k : string]: any}): void {}  

which looks like

{    "kind": 190,    "kindStr": "MappedType",    "childkeys": [      "typeParameter",      "type"    ],    "typeParameter": {      "kind": 159,      "kindStr": "TypeParameter",      "childkeys": [        "name",        "constraint"      ],      "name": {        "kind": 78,        "kindStr": "Identifier",        "symbolref": {          "id": -1,          "name": "k",          "flagStrings": [            "TypeParameter"          ],          "flags": 262144        }      },      "constraint": {        "kind": 147,        "kindStr": "StringKeyword"      }    },    "type": {      "kind": 128,      "kindStr": "AnyKeyword"    }  }  

I read the answer to a similar question, but haven't managed to apply it correctly. (That question & answer didn't use ts-morph but I think ts-morph should have equivalent capability using ts-morph.Symbol#getTypeAtLocation.)

I have tried the following using the ts-morph module:

  const expsymbols = sourceFile.getExportSymbols();    const decl = expsymbols[0].getDeclarations()[0]!;    t.assert.ok(tsm.Node.isFunctionDeclaration(decl));      decl.getParameters().forEach((p) => {      const type1 = p        .getNameNode()        .getSymbol()!        .getTypeAtLocation(p.getNameNode());      const type1Decl = type1.getSymbol()!.getDeclarations()[0];      t.comment(`-----------1------------`);      t.comment(makePrintable(type1Decl.compilerNode, checker.compilerObject))        const type2 = p.getType();      const type2Decl = type2.getSymbol()!.getDeclarations()[0];      t.comment(`-----------2------------`);      t.comment(makePrintable(type2Decl.compilerNode, checker.compilerObject))        const type3 = p        .getNameNode()        .getSymbol()!        .getTypeAtLocation(p.getTypeNode()!);      const type3Decl = type3.getSymbol()!.getDeclarations()[0];      t.comment(`-----------3------------`);      t.comment(makePrintable(type2Decl.compilerNode, checker.compilerObject))    

All approaches 1,2,3 produce the same output as follows, and don't substitute 'string' for 'K' and 'any' for 'T'. I think that the solution is to point the right function at the right location, but further attempts have so far produced only errors. Any advice would be appreciated.

#    -----------3------------  #    {  #      "kind": 190,  #      "kindStr": "MappedType",  #      "childkeys": [  #        "typeParameter",  #        "type"  #      ],  #      "typeParameter": {  #        "kind": 159,  #        "kindStr": "TypeParameter",  #        "childkeys": [  #          "name",  #          "constraint"  #        ],  #        "name": {  #          "kind": 78,  #          "kindStr": "Identifier",  #          "symbolref": {  #            "id": -1,  #            "name": "P",  #            "flagStrings": [  #              "TypeParameter"  #            ],  #            "flags": 262144  #          }  #        },  #        "constraint": {  #          "kind": 173,  #          "kindStr": "TypeReference",  #          "childkeys": [  #            "typeName"  #          ],  #          "typeName": {  #            "kind": 78,  #            "kindStr": "Identifier",  #            "symbolref": {  #              "id": 1,  #              "name": "K",  #              "flagStrings": [  #                "TypeParameter"  #              ],  #              "flags": 262144  #            }  #          }  #        }  #      },  #      "type": {  #        "kind": 173,  #        "kindStr": "TypeReference",  #        "childkeys": [  #          "typeName"  #        ],  #        "typeName": {  #          "kind": 78,  #          "kindStr": "Identifier",  #          "symbolref": {  #            "id": 2,  #            "name": "T",  #            "flagStrings": [  #              "TypeParameter"  #            ],  #            "flags": 262144  #          }  #        }  #      }  #    }  

File node tree

{    "kind": 251,    "kindStr": "FunctionDeclaration",    "childkeys": [      "modifiers",      "name",      "parameters",      "type",      "body"    ],    "modifiers": [      {        "kind": 92,        "kindStr": "ExportKeyword"      }    ],    "name": {      "kind": 78,      "kindStr": "Identifier",      "symbolref": {        "id": -1,        "name": "fn_record",        "flagStrings": [          "Function"        ],        "flags": 16      }    },    "parameters": [      {        "kind": 160,        "kindStr": "Parameter",        "childkeys": [          "name",          "type"        ],        "name": {          "kind": 78,          "kindStr": "Identifier",          "symbolref": {            "id": -1,            "name": "a",            "flagStrings": [              "FunctionScopedVariable"            ],            "flags": 1          }        },        "type": {          "kind": 173,          "kindStr": "TypeReference",          "childkeys": [            "typeName",            "typeArguments"          ],          "typeName": {            "kind": 78,            "kindStr": "Identifier",            "symbolref": {              "id": 1,              "name": "Record",              "flagStrings": [                "TypeAlias"              ],              "flags": 524288            }          },          "typeArguments": [            {              "kind": 147,              "kindStr": "StringKeyword"            },            {              "kind": 128,              "kindStr": "AnyKeyword"            }          ]        }      }    ],    "type": {      "kind": 113,      "kindStr": "VoidKeyword"    },    "body": {      "kind": 230,      "kindStr": "Block"    }  }  

https://stackoverflow.com/questions/65745804/typescript-ts-morph-resolving-parameter-type-in-export-function-fn-recorda January 16, 2021 at 10:03AM