sentence-splitter

Split {Japanese, English} text into sentences.

Installation

npm install sentence-splitter

Requirements:

• Array.from
• Array#fill

CLI

$ npm install -g sentence-splitter
$ echo "This is a pen. But, this is not pen" | sentence-splitter
This is a pen.
But This is not pen

Usage

export interface SeparatorParserOptions {
    /**
     * Recognize each characters as separator
     * Example [".", "!", "?"]
     */
    separatorCharacters?: string[]
}

export interface splitOptions {
    /**
     * Separator options
     */
    SeparatorParser?: SeparatorParserOptions;
}

/**
 * split `text` into Sentence nodes
 */
export declare function split(text: string, options?: splitOptions): (TxtParentNode | TxtNode)[];

/**
 * Convert Paragraph Node to Paragraph node that convert children to Sentence node
 * This Node is based on TxtAST.
 * See https://github.com/textlint/textlint/blob/master/docs/txtnode.md
 */
export declare function splitAST(paragraphNode: TxtParentNode, options?: splitOptions): TxtParentNode;

TxtParentNode and TxtNode is defined in TxtAST.

Example

import { split, Syntax } from "sentence-splitter";

let sentences = split(`There it is! I found it.
Hello World. My name is Jonas.`);
console.log(JSON.stringify(sentences, null, 4));
/*
{
    "type": "Paragraph",
    "children": [
        {
            "type": "Sentence",
            "raw": "There it is!",
            "value": "There it is!",
            "loc": {
                "start": {
                    "line": 1,
                    "column": 0
                },
                "end": {
                    "line": 1,
                    "column": 12
                }
            },
            "range": [
                0,
                12
            ],
            "children": [
                {
                    "type": "Str",
                    "raw": "There it is",
                    "value": "There it is",
                    "loc": {
                        "start": {
                            "line": 1,
                            "column": 0
                        },
                        "end": {
                            "line": 1,
                            "column": 11
                        }
                    },
                    "range": [
                        0,
                        11
                    ]
                },
                {
                    "type": "Punctuation",
                    "raw": "!",
                    "value": "!",
                    "loc": {
                        "start": {
                            "line": 1,
                            "column": 11
                        },
                        "end": {
                            "line": 1,
                            "column": 12
                        }
                    },
                    "range": [
                        11,
                        12
                    ]
                }
            ]
        },
        {
            "type": "WhiteSpace",
            "raw": " ",
            "value": " ",
            "loc": {
                "start": {
                    "line": 1,
                    "column": 12
                },
                "end": {
                    "line": 1,
                    "column": 13
                }
            },
            "range": [
                12,
                13
            ]
        },
        {
            "type": "Sentence",
            "raw": "I found it.\nHello World.",
            "value": "I found it.\nHello World.",
            "loc": {
                "start": {
                    "line": 1,
                    "column": 13
                },
                "end": {
                    "line": 2,
                    "column": 12
                }
            },
            "range": [
                13,
                37
            ],
            "children": [
                {
                    "type": "Str",
                    "raw": "I found it.",
                    "value": "I found it.",
                    "loc": {
                        "start": {
                            "line": 1,
                            "column": 13
                        },
                        "end": {
                            "line": 1,
                            "column": 24
                        }
                    },
                    "range": [
                        13,
                        24
                    ]
                },
                {
                    "type": "WhiteSpace",
                    "raw": "\n",
                    "value": "\n",
                    "loc": {
                        "start": {
                            "line": 1,
                            "column": 24
                        },
                        "end": {
                            "line": 2,
                            "column": 0
                        }
                    },
                    "range": [
                        24,
                        25
                    ]
                },
                {
                    "type": "Str",
                    "raw": "Hello World",
                    "value": "Hello World",
                    "loc": {
                        "start": {
                            "line": 2,
                            "column": 0
                        },
                        "end": {
                            "line": 2,
                            "column": 11
                        }
                    },
                    "range": [
                        25,
                        36
                    ]
                },
                {
                    "type": "Punctuation",
                    "raw": ".",
                    "value": ".",
                    "loc": {
                        "start": {
                            "line": 2,
                            "column": 11
                        },
                        "end": {
                            "line": 2,
                            "column": 12
                        }
                    },
                    "range": [
                        36,
                        37
                    ]
                }
            ]
        },
        {
            "type": "WhiteSpace",
            "raw": " ",
            "value": " ",
            "loc": {
                "start": {
                    "line": 2,
                    "column": 12
                },
                "end": {
                    "line": 2,
                    "column": 13
                }
            },
            "range": [
                37,
                38
            ]
        },
        {
            "type": "Sentence",
            "raw": "My name is Jonas.",
            "value": "My name is Jonas.",
            "loc": {
                "start": {
                    "line": 2,
                    "column": 13
                },
                "end": {
                    "line": 2,
                    "column": 30
                }
            },
            "range": [
                38,
                55
            ],
            "children": [
                {
                    "type": "Str",
                    "raw": "My name is Jonas",
                    "value": "My name is Jonas",
                    "loc": {
                        "start": {
                            "line": 2,
                            "column": 13
                        },
                        "end": {
                            "line": 2,
                            "column": 29
                        }
                    },
                    "range": [
                        38,
                        54
                    ]
                },
                {
                    "type": "Punctuation",
                    "raw": ".",
                    "value": ".",
                    "loc": {
                        "start": {
                            "line": 2,
                            "column": 29
                        },
                        "end": {
                            "line": 2,
                            "column": 30
                        }
                    },
                    "range": [
                        54,
                        55
                    ]
                }
            ]
        }
    ],
    "loc": {
        "start": {
            "line": 1,
            "column": 0
        },
        "end": {
            "line": 2,
            "column": 30
        }
    },
    "range": [
        0,
        55
    ],
    "raw": "There it is! I found it.\nHello World. My name is Jonas."
}
*/

Node

This node is based on TxtAST.

Node's type

• Str: Str node has value
• Sentence: Sentence Node has Str, WhiteSpace, or Punctuation nodes as children
• WhiteSpace: WhiteSpace Node has \n.
• Punctuation: Punctuation Node has ., 。

Get these Syntax constants value from the module:

import { Syntax } from "sentence-splitter";

console.log(Syntax.Sentence);// "Sentence"

Node's interface

export interface WhiteSpaceNode extends TxtTextNode {
    readonly type: "WhiteSpace";
}

export interface PunctuationNode extends TxtTextNode {
    readonly type: "Punctuation";
}

export interface StrNode extends TxtTextNode {
    readonly type: "Str";
}

export interface SentenceNode extends TxtParentNode {
    readonly type: "Sentence";
}

Fore more details, Please see TxtAST.

Node layout

Node layout image.

<WhiteSpace />
<Sentence>
    <Str />
    <Punctuation />
    <Str />
    <Punctuation />
</Sentence>
<WhiteSpace />

Note: This library will not split Str into Str and WhiteSpace(tokenize) Because, Tokenize need to implement language specific context.

in textlint rule

You can use splitAST in textlint rule. splitAST function can preverse original AST's position unlike split function.

import { splitAST, Syntax as SentenceSyntax } from "sentence-splitter";

export default function(context, options = {}) {
    const { Syntax, RuleError, report, getSource } = context;
    return {
        [Syntax.Paragraph](node) {
            const resultNode = splitAST(node);
            const sentenceNodes = resultNode.children.filter(childNode => childNode.type === SentenceSyntax.Sentence);
            console.log(sentenceNodes); // => Sentence nodes
        }
    }
}

Example

• textlint-ja/textlint-rule-max-ten: textlint rule that limit maxinum ten(、) count of sentence.

Reference

This library use "Golden Rule" test of pragmatic_segmenter.

• diasks2/pragmatic_segmenter: Pragmatic Segmenter is a rule-based sentence boundary detection gem that works out-of-the-box across many languages.

Tests

Run tests:

npm test

Create input.json from _input.md

npm run createInputJson    

Update snapshots(output.json):

npm run updateSnapshot

Adding snapshot testcase

1. Create test/fixtures/<test-case-name>/ directory
2. Put test/fixtures/<test-case-name>/_input.md with testing content
3. Run npm run updateSnapshot
4. Check the test/fixtures/<test-case-name>/output.json
5. If it is ok, commit it

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

License

MIT