feat(eslint-plugin): Add unified-signature rule

[armanio123]

Adding tslint's rule unified-signature.

[armano2]

i'm unsure if this implementation is best what we can do in here

its weird that we have to iterate over nodes few times

this is just idea and i didn't tested it but it should work:

    const scopes = [];
    let currentScope = {
      overloads: new Map(),
      parent: undefined,
      typeParameters: undefined
    };

    function createScope(parent, typeParameters = undefined) {
      scopes.push(currentScope);
      currentScope = {
        overloads: new Map(),
        parent,
        typeParameters
      };
    }

    function checkScope() {
      const failures = checkOverloads(
        Array.from(currentScope.overloads.values()),
        currentScope.typeParameters
      );
      addFailures(failures);
      currentScope = scopes.pop();
    }

    function addOverload(signature, key = null) {
      key = key || getOverloadKey(signature);
      if (signature.parent === currentScope.parent && key) {
        const overloads = currentScope.overloads.get(key);
        if (overloads !== undefined) {
          overloads.push(signature);
        } else {
          currentScope.overloads.set(key, [signature]);
        }
      }
    }

    return {
      Program(node) {
        createScope(node);
      },
      TSModuleBlock(node) {
        createScope(node);
      },
      TSInterfaceDeclaration(node) {
        createScope(node.body, node.typeParameters);
      },
      ClassDeclaration(node) {
        createScope(node.body, node.typeParameters);
      },
      TSTypeLiteral(node) {
        createScope(node);
      },
      // collect overloads
      TSDeclareFunction(node) {
        if (node.id && !node.body) {
          addOverload(node, node.id.name);
        }
      },
      TSCallSignatureDeclaration: addOverload,
      TSConstructSignatureDeclaration: addOverload,
      TSMethodSignature: addOverload,
      TSAbstractMethodDefinition(node) {
        if (!node.value.body) {
          addOverload(node);
        }
      },
      MethodDefinition(node) {
        if (!node.value.body) {
          addOverload(node);
        }
      },
      // validate scopes
      'Program:exit': checkScope,
      'TSModuleBlock:exit': checkScope,
      'TSInterfaceDeclaration:exit': checkScope,
      'ClassDeclaration:exit': checkScope,
      'TSTypeLiteral:exit': checkScope
    };

i still don't like this code, but at-least we don't have to iterate over nodes with custom implementation

with that you are going to be able to remove: checkStatements, checkMembers, collectOverloads.

[JamesHenry]

Apologies for the conflicts, we decided to remove the counts from the ROADMAP here: #225

They are too awkward to maintain manually, so this is the last time you will have to deal with syncing that up!

Stale

[JamesHenry]

@armanio123 Thanks again for your contribution, when do you think you'll be able to pick this up again?

[JamesHenry]

Sorry we've changed to using all-contributors now and removed all other occurrences of these file-level author comments, please could you remove this

[armanio123]

Removed.

[armanio123]

Added the changes requested, migrated to TS and addressed the comments as well. Let me know if there's anything else.

[codecov]

Codecov Report

Merging #178 into master will decrease coverage by <.01%.
The diff coverage is 97.16%.

@@            Coverage Diff            @@
##           master    #178      +/-   ##
=========================================
- Coverage    97.2%   97.2%   -0.01%     
=========================================
  Files          67      68       +1     
  Lines        2360    2501     +141     
  Branches      337     385      +48     
=========================================
+ Hits         2294    2431     +137     
  Misses         44      44              
- Partials       22      26       +4

Impacted Files	Coverage Δ
packages/eslint-plugin/src/util/misc.ts	84.21% <100%> (+4.21%)	⬆️
...ages/eslint-plugin/src/rules/unified-signatures.ts	97.08% <97.08%> (ø)

[bradzacher]

need to add the link at the bottom of the file or else this won't work

[armanio123]

Fixed.

[bradzacher]

need to tighten up the types if this is going to be merged.
Most of the functions have params of type any. Ideally there should be zero anys.

You can import { TSESTree } from '@typescript-eslint/typescript-estree'; and use the types within that namespace to type nodes and the like.

[JamesHenry]

Thanks for working through all the feedback, @armanio123!

[JamesHenry]

@uniqueiniquity is going to apply this to the TS repo this week :)