New: no-unused-vars (fixes #100).

[aladdin-add]

fixes #100

almost finished.:)

I'm not very familiar with the ASTs, so please let me know if missing something.

[armano2]

@aladdin-add you are missing tests for nested interations

from what i understund you are doing alot recursive loops with collectUsed.
There is 2 fields witch can come in handy for this:
https://github.com/mysticatea/vue-eslint-parser/blob/master/docs/ast.md#vexpressioncontainer
-> Reference

or:
get all properties and declarations + at end compare them (it will avoid recursive loops)

[aladdin-add]

SGTM. is there a way to get all properties and {{}}? (seems it also need recurse, and it's that function collectUsed is doing)

[armano2]

@aladdin-add

VElement (node) {
  if (node.variables) {
    for (const variable of node.variables) {
      variables.push(varNode)
    }
  }
},

[aladdin-add]

I was a little confused. seems it's just declared variables in the element, and didn't include the inside ones.

let's be clear, we need to scan every inside elements(and inside), to check if it is used. (hope it can has a function in ast-utils to get all).

[armano2]

@aladdin-add
whats about:

function create (context) {
  let stack = []
  let unused = []

  return utils.defineTemplateBodyVisitor(context, {
    'VElement:exit' () {
      for (const node of unused) {
        context.report({
          node,
          loc: node.loc,
          message: `'{{name}}' is defined but never used.`,
          data: {
            name: node.name
          }
        })
      }
      unused = stack.pop()
    },
    VElement (node) {
      stack.push(unused)
      unused = []
      if (node.variables) {
        for (const variable of node.variables) {
          unused.push(variable.id)
        }
      }
    },
    VExpressionContainer (node) {
      if (node.references) {
        for (const reference of node.references) {
          if (reference.mode !== 'w') {
            const name = reference.id.name
            unused = unused.filter((el) => el.name !== name)
            stack = stack.map((obj) => obj.filter((el) => el.name !== name))
          }
        }
      }
    }
  })
}

btw. please merge code with master 🗡 there is nice update to parser there

[aladdin-add]

great! and it looks better!

[armano2]

can you add few more tests ?

-> nested v-for and multiple scopes ?
v-for > v-for > [scope]

and usage of foo.bar.baz

[armano2]

and test for:

<template><ol v-for="i in data"><li v-for="f in i">{{ f.bar.baz }}</li></ol></template>

[mysticatea]

Thank you for contributing!

I'm sorry for late response.

I think we can simplify this rule.

return utils.defineTemplateBodyVisitor(context, {
    VElement(node) {
        for (const variable of node.variables) {
            if (variable.references.length === 0) {
                context.report({
                    node: variable.id,
                    loc: variable.id.loc,
                    message: `'{{name}}' is defined but never used.`,
                    data: variable.id
                })
            }
        }
    }
})

[armano2]

@aladdin-add we are missing one more test:

<template><div v-for="(v, i, c) in foo"></div></template>

should warn about 3 unused variables

[mysticatea]

LGTM, thank you!