HtmlToText React Native Reference Documentation

HtmlToText

Current Version: 11.6.1

Chilkat.HtmlToText

Convert HTML into readable plain text with control over links, wrapping, and encoding.

Chilkat.HtmlToText converts HTML content into readable plain text. It can decode HTML entities, wrap output at a configurable right margin, optionally include or suppress hyperlink URLs, convert HTML supplied as a string or StringBuilder, and read or write files using an explicit character encoding.

HTML to plain text

Convert HTML markup into readable text suitable for display, logging, indexing, email alternatives, or text-only output.

Entity decoding

Decode HTML entities so text such as named entities and numeric character references becomes normal readable output.

Line wrapping

Use RightMargin to wrap text at a chosen width, or set it to 0 when no right-margin wrapping is wanted.

Link handling

Suppress hyperlink URLs for cleaner text, or emit URLs when the output needs to preserve the destination of HTML links.

StringBuilder support

Convert HTML directly from a StringBuilder when working with larger or incrementally built HTML content.

File and charset helpers

Read HTML from files and write text output using a specified character encoding.

Common pattern: Provide the HTML as a string, file, or StringBuilder, choose whether to decode entities and include link URLs, set the desired right margin, then convert the result to plain text. Use HtmlToText when the goal is readable text, not structured XML or DOM-style parsing.

For an extended overview, see HtmlToText Class Overview.

Object Creation

// npm install @chilkat/react-native react-native-nitro-modules
// (React Native 0.76+ with the New Architecture; then `pod install` for iOS.  The Chilkat
//  native library is downloaded and verified during the native build -- see the package README.)

import { Chilkat, HtmlToText } from '@chilkat/react-native'

// Once per app start, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial')   // shorthand for new Global().unlockBundle(..)

const htmlToText = new HtmlToText()
// ... the native object is released when `htmlToText` is garbage collected, or now with htmlToText.dispose()

new HtmlToText()

Creates the underlying native Chilkat object. HtmlToText is a Nitro Module HybridObject: use it from the JavaScript thread only (it cannot be passed to a Worklet or another runtime). Every member is synchronous and blocks the JavaScript thread until Chilkat returns; a method that can take a while also exists as a ...Async twin returning a Promise, which runs the same call on a native worker thread so the UI keeps rendering. While such a call is pending, every other call on this object throws, except abort() and assigning onPercentDone / onProgressInfo.

dispose(): void

Releases the native object immediately instead of waiting for garbage collection (useful for a large BinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws. An object with a pending ...Async call cannot be disposed until the promise settles.

Errors

A method that can fail throws a plain Error: a method whose only outcome is success or failure returns void and throws on failure; a method producing a string or an object returns it and throws where Chilkat would have returned null. The error's message is "Class.method(...): reason", where the reason is the last informative line of the object's lastErrorText, which holds the full Chilkat log of the failed call. A ...Async twin rejects its promise with the same Error instead of throwing. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain boolean.

try {
  htmlToText.someMethod(...)
} catch (e) {
  console.log((e as Error).message)   // HtmlToText.someMethod(...): <reason>
  console.log(htmlToText.lastErrorText)   // the full Chilkat log of the failed call
}

// The same call without blocking the JavaScript thread:
try {
  await htmlToText.someMethodAsync(...)
} catch (e) {
  console.log((e as Error).message)   // HtmlToText.someMethodAsync: <reason>
}

Properties

DebugLogFilePath

// read/write
debugLogFilePath: string

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

A timeout property set to 0, indicating an infinite timeout.
A hang occurring within an event callback in the application code.
An internal bug in the Chilkat code causing the hang.

More Information and Examples

Example showing how to use DebugLogFilePath.

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DecodeHtmlEntities

// read/write
decodeHtmlEntities: boolean

Controls whether HTML character references are decoded when converting HTML to plain text. The default value is true.

Value	Behavior
`true`	HTML entities and numeric character references are decoded to their corresponding characters. For example, `&` becomes `&`.
`false`	Character references are left encoded in the plain-text output.

Typical use: Leave this property set to true when the goal is human-readable text. Set it to false when the original entity notation itself must be preserved.

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LastErrorHtml

// read-only
readonly lastErrorHtml: string

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText

// read-only
readonly lastErrorText: string

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

More Information and Examples

Concept of LastErrorText LastErrorText Standard Information

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LastErrorXml

// read-only
readonly lastErrorXml: string

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess

// read/write
lastMethodSuccess: boolean

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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RightMargin

// read/write
rightMargin: number

Controls line wrapping in the generated plain text. The default value is 80. As a line approaches the configured margin, Chilkat attempts to wrap at a SPACE character. Set this property to 0 to disable right-margin wrapping.

Soft margin: The right margin is a preferred wrapping point, not a guaranteed maximum line length. A long sequence with no suitable SPACE character may extend beyond the configured margin.

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SuppressLinks

// read/write
suppressLinks: boolean

Controls whether hyperlink destination URLs are included in the generated plain text. The default value is true.

Value	Behavior
`true`	The visible anchor text is retained, but hyperlink destination URLs are omitted.
`false`	Hyperlink URLs are included. By default, they are collected in a `References:` section at the end of the plain text.

For example, with SuppressLinks set to false, an HTML link whose visible text is chilkat and whose URL is https://www.chilkatsoft.com/ produces the visible text and a numbered reference at the end of the output.

Related options: When link URLs are enabled, UncommonOptions can be used to suppress the trailing references list with NoReferencesList or emit URLs inline with EmitUrls.

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UncommonOptions

// read/write
uncommonOptions: string

Introduced in version 11.0.0

Specifies uncommon HTML-to-text conversion options as a comma-separated list of keywords. The default is the empty string, which is appropriate for normal use.

Keyword	Effect
`NoReferencesList`	Does not generate the hyperlink-reference list at the end of the plain-text output.
`EmitUrls`	Emits hyperlink URLs inline in the plain-text output instead of relying on the default trailing reference list.

Interaction with SuppressLinks: These options control the presentation of hyperlink URLs when URL output is enabled. If SuppressLinks is true, hyperlink URLs are suppressed.

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VerboseLogging

// read/write
verboseLogging: boolean

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version

// read-only
readonly version: string

Version of the component/library, such as "10.1.0"

More Information and Examples

How to get the Chilkat version at runtime.

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Methods

ToText

toText(html: string): string

Converts the HTML in html to readable plain text and returns the result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions. HTML markup is interpreted to produce readable text rather than simply being removed with a tag-stripping operation.

Plain-text conversion: The output is intended for reading, indexing, logging, email text alternatives, and similar text-oriented uses. It is not intended to preserve the original HTML markup or visual layout exactly.

Throws an Error on failure (where the description says null is returned, the method throws instead).

More Information and Examples

HTML Tables to Plain Text Conversion Gallery

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ToTextSb

toTextSb(sb: StringBuilder): void

Introduced in version 9.5.0.97

Converts the HTML currently contained in sb to plain text in place. On success, the same StringBuilder contains the converted plain-text result. The conversion honors DecodeHtmlEntities, RightMargin, SuppressLinks, and UncommonOptions.

StringBuilder workflow: Use this method when the HTML is already held in a StringBuilder and you want the conversion result returned through that same object rather than as a separate string.

Returns normally on success; throws an Error on failure.

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