@putout/operator-declare

🐊Putout operator adds ability to declare variables that has references with no definitions. Most likely you prefer using Declarator plugin type based on current Operator.

Install

npm i putout @putout/operator-declare

API

If you want to create 🐊Putout plugin that will declare variables according to your needs just:

import {operator} from 'putout';

const {declare} = operator;

export const {
    report,
    include,
    fix,
    filter,
} = declare({
    fs: `import fs from 'fs/promises'`,
});

nearby

By default @putout/operator-declare declares variables on the top level, when you need to declare on the same level,

export const FunctionDeclaration = {
    print(path, printer, semantics) {
        const {
+           indent
            print,
        } = printer;
        indent();
    }
}

Use nearby:

const {operator} = require('putout');
const {declare} = operator;

export const {
    report,
    include,
    fix,
    filter,
} = declare({
    indent: ['const {indent} = printer', {
        nearby: true,
    }],
});

Dual packages

When you need different declarations for ESM and CommonJS you can use:

const {operator} = require('putout');
const {declare} = operator;

export const {
    report,
    include,
    fix,
    filter,
} = declare({
    fs: {
        esm: `import fs from 'fs/promises'`,
        comomnjs: `const fs = require('fs')`, // drop when not needed
    },
});

Configuration

Plugin supports options, so you can pass it in .putout.json:

{
    "rules": {
        "putout/declare": ["on", {
            "declarations": {
                "fs": "import fs from 'fs/promises'"
            }
        }]
    }
}

If for some reason you don't need some kind of declaration, add dismiss field and it will be ignored:

{
    "rules": {
        "putout/declare": ["on", {
            "declarations": {
                "fs": "import fs from 'fs/promises'"
            },
            "dismiss": ["fs"]
        }]
    }
}

If you want to override type to avoid detecting, set it to esm|commonjs:

{
    "rules": {
        "putout/declare": ["on", {
            "declarations": {
                "fs": "import fs from 'fs/promises'"
            },
            "dismiss": ["fs"],
            "type": "esm"
        }]
    }
}

top

When you need to put declaration on top:

+{defineProperty} = Object;
defineProperty(require, '__esModule', {
    value: true,
});
require.require = require;
const a = require('hello');

console.log(a);

function require(a) {
    return a;
}

Use nearby:

const {operator} = require('putout');
const {declare} = operator;

export const {
    report,
    include,
    fix,
    filter,
} = declare({
    defineProperty: ['const {defineProperty} = Object', {
        top: true,
    }],
});

Used in

• ✅ declare
• ✅ tape/declare
• ✅ putout/declare
• ✅ nodejs/declare
• ✅ react-hooks/declare
• ✅ try-catch/declare
• ✅ montag/declare
• ✅ madrun/declare
• ✅ maybe/declare

Evaluate

Can be used with ESLint's putout/evaluate:

{
    "rules": {
        "putout/declare": ["on", {
            "declarations": {
                "superMethod": "import superMethod from '__putout_evaluate: join(`./`, basename(__filename), `.js`)'"
            }
        }]
    }
}

If you have a file index.spec.js:

+ import superMethod from './index.js'
superMethod();

License

MIT