plugin-proposal-pipeline-operator.md

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---
id: babel-plugin-proposal-pipeline-operator
title: @babel/plugin-proposal-pipeline-operator
sidebar_label: pipeline-operator
---

Installation

$ npm install --save-dev @babel/plugin-proposal-pipeline-operator

Usage

The pipeline operator has several competing proposals. Configure which proposal to use with the required "proposal" option.

Value	Proposal	Version added
"minimal"	Minimal F#-style pipes	v7.0.0
"fsharp"	F#-style pipes with await	v7.5.0
"hack"	Hack-style pipes	v7.15.0
"smart"	Smart-mix pipes (deprecated)	v7.3.0

If "proposal": "hack" is used, then a "topicToken": "%", "topicToken": "^", or "topicToken": "#" option must also be included.

The "proposal": "smart" option is deprecated and subject to removal in a future major version.

When TC39 accepts one of the proposals, that proposal will become the default and the "proposal" option will no longer be required.

Summary of proposals’ behavior

Original expression	Minimal F# pipes {proposal: "minimal"}	F# pipes with await {proposal: "fsharp"}	Hack pipes {proposal: "hack", topicToken: "%"}
o.m(x)	x |> o.m	x |> o.m	x |> o.m(%)
o.m(0, x)	x |> y=>o.m(0, y)	x |> y=>o.m(0, y)	x |> o.m(0, %)
new o.m(x)	x |> y=>new o.m(y)	x |> y=>new o.m(y)	x |> new o.m(%)
o[x]	x |> y=>o[x]	x |> y=>o[y]	x |> o[%]
x[i]	x |> y=>x[i]	x |> y=>y[i]	x |> %[i]
x + 1	x |> y=>y + 1	x |> y=>y + 1	x |> % + 1
[0, x]	x |> y=>[0, y]	x |> y=>[0, y]	x |> [0, %]
{ key: x }	x |> y=>({ key: y })	x |> y=>({ key: y })	x |> { key: % }
await o.m(x)	Not supported	x |> o.m |> await	x |> await o.m(%)
yield o.m(x)	Not supported	Not supported	x |> (yield o.m(%))

With a configuration file (Recommended)

For minimal F# pipes:

{
  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "minimal" }]
  ]
}

For F# pipes with await:

{
  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "fsharp" }]
  ]
}

For Hack pipes with % topic token:

{
  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "hack", "topicToken": "%" }]
  ]
}

For Hack pipes with ^ topic token:

{
  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "hack", "topicToken": "^" }]
  ]
}

For Hack pipes with # topic token:

{
  "plugins": [
    ["@babel/plugin-proposal-pipeline-operator", { "proposal": "hack", "topicToken": "#" }]
  ]
}

Via CLI

Because this plugin requires a configuration option, it cannot be directly configured from the CLI. Use a config file instead with the CLI, to add and configure this plugin.

Via Node API

For minimal F# pipes
{proposal: "minimal"}:

require("@babel/core").transformSync("code", {
  plugins: [
    [ "@babel/plugin-proposal-pipeline-operator", { proposal: "minimal" } ],
  ],
});

For F# pipes with await:

require("@babel/core").transformSync("code", {
  plugins: [
    [ "@babel/plugin-proposal-pipeline-operator", { proposal: "fsharp" } ],
  ],
});

For Hack pipes with % topic token:

require("@babel/core").transformSync("code", {
  plugins: [
    [ "@babel/plugin-proposal-pipeline-operator", { proposal: "hack", topicToken: "%" } ],
  ],
});

For Hack pipes with ^ topic token:

require("@babel/core").transformSync("code", {
  plugins: [
    [ "@babel/plugin-proposal-pipeline-operator", { proposal: "hack", topicToken: "^" } ],
  ],
});

For Hack pipes with # topic token:

require("@babel/core").transformSync("code", {
  plugins: [
    [ "@babel/plugin-proposal-pipeline-operator", { proposal: "hack", topicToken: "#" } ],
  ],
});