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Advanced Options

Advanced Options

In TextWrap, the wrap(), fill(), and shorten() methods are designed to offer flexible text formatting. Beyond basic usage, these functions provide advanced options that give you fine control over how text is processed and formatted.

Supported Options

  • width
    (default: 70) – The maximum length of wrapped lines. As long as there are no individual words in the input text longer than width, TextWrap guarantees that no output line will be longer than width characters.

  • expand_tabs
    (default: true) – If true, then all tab characters in text will be expanded to spaces using the expandTabs() method of text.

  • tabsize
    (default: 8) – If expand_tabs is true, then all tab characters in text will be expanded to zero or more spaces, depending on the current column and the given tab size.

  • replace_whitespace
    (default: true) – If true, after tab expansion but before wrapping, the wrap(), fill(), or shorten() methods will replace each whitespace character with a single space. The whitespace characters replaced are as follows: tab, newline, vertical tab, formfeed, and carriage return ('\t\n\v\f\r').

    ℹ️
    If expand_tabs is false and replace_whitespace is true, each tab character will be replaced by a single space, which is not the same as tab expansion.

    ℹ️
    If replace_whitespace is false, newlines may appear in the middle of a line and cause strange output. For this reason, text should be split into paragraphs (using String.splitLines() or similar) which are wrapped separately.

  • drop_whitespace
    (default: true) – If true, whitespace at the beginning and ending of every line (after wrapping but before indenting) is dropped. Whitespace at the beginning of the paragraph, however, is not dropped if non-whitespace follows it. If whitespace being dropped takes up an entire line, the whole line is dropped.

  • initial_indent
    (default: '') – String that will be prepended to the first line of wrapped output. Counts towards the length of the first line. The empty string is not indented.

  • subsequent_indent
    (default: '') – String that will be prepended to all lines of wrapped output except the first. Counts towards the length of each line except the first.

  • fix_sentence_endings
    (default: false) – If true, TextWrap attempts to detect sentence endings and ensure that sentences are always separated by exactly two spaces. This is generally desired for text in a monospaced font. However, the sentence detection algorithm is imperfect: it assumes that a sentence ending consists of a lowercase letter followed by one of '.', '!', or '?', possibly followed by one of '"' or "'", followed by a space. One problem with this algorithm is that it is unable to detect the difference between “Dr.” in

    [...] Dr. Frankenstein's monster [...]
    [...] See Spot. See Spot run [...]

    fix_sentence_endings is false by default.
    Since the sentence detection algorithm relies on String.toLowerCase for the definition of “lowercase letter”, and a convention of using two spaces after a period to separate sentences on the same line, it is specific to English-language texts.

  • break_long_words
    (default: true) – If true, then words longer than width will be broken in order to ensure that no lines are longer than width. If it is false, long words will not be broken, and some lines may be longer than width. (Long words will be put on a line by themselves, in order to minimize the amount by which width is exceeded).

  • break_on_hyphens
    (default: true) – If true, wrapping will occur preferably on whitespaces and right after hyphens in compound words, as it is customary in English. If false, only whitespaces will be considered as potentially good places for line breaks, but you need to set break_long_words to false if you want truly insecable words. Default behaviour in previous versions was to always allow breaking hyphenated words.

  • max_lines
    (default: null) – If not null, then the output will contain at most max_lines lines, with placeholder appearing at the end of the output.

  • placeholder
    (default: ' [...]') String that will appear at the end of the output text if it has been truncated.

Basic Usage

example.js
const text = "This is a long line of text that needs\tto be wrapped properly\twithout cutting\twords in half.";
const options = {
  replace_whitespace: false,
  tabsize: 12,
  initial_indent: "[!] "
}
const wrapped = textwrap.wrap(text, 20, options)

console.log(wrapped);

Result:

[
  '[!] This is a long',
  'line of text that',
  'needs          to be',
  'wrapped properly',
  'without cutting',
  'words in half.'
]

Another example:

example.js
const text = "This is a long piece of text that needs to be shortened for display purposes.";
const options = {
  placeholder: " (...)"
};
const shortened = textwrap.shorten(text, 30, options);

console.log(shortened);

Result:

This is a long piece of (...)
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