| # jsonc-parser | |
| Scanner and parser for JSON with comments. | |
| [](https://www.npmjs.org/package/jsonc-parser) | |
| [](https://npmjs.org/package/jsonc-parser) | |
| [](https://github.com/microsoft/node-jsonc-parser/workflows/Tests) | |
| [](https://opensource.org/licenses/MIT) | |
| Why? | |
| ---- | |
| JSONC is JSON with JavaScript style comments. This node module provides a scanner and fault tolerant parser that can process JSONC but is also useful for standard JSON. | |
| - the *scanner* tokenizes the input string into tokens and token offsets | |
| - the *visit* function implements a 'SAX' style parser with callbacks for the encountered properties and values. | |
| - the *parseTree* function computes a hierarchical DOM with offsets representing the encountered properties and values. | |
| - the *parse* function evaluates the JavaScript object represented by JSON string in a fault tolerant fashion. | |
| - the *getLocation* API returns a location object that describes the property or value located at a given offset in a JSON document. | |
| - the *findNodeAtLocation* API finds the node at a given location path in a JSON DOM. | |
| - the *format* API computes edits to format a JSON document. | |
| - the *modify* API computes edits to insert, remove or replace a property or value in a JSON document. | |
| - the *applyEdits* API applies edits to a document. | |
| Installation | |
| ------------ | |
| ``` | |
| npm install --save jsonc-parser | |
| ``` | |
| API | |
| --- | |
| ### Scanner: | |
| ```typescript | |
| /** | |
| * Creates a JSON scanner on the given text. | |
| * If ignoreTrivia is set, whitespaces or comments are ignored. | |
| */ | |
| export function createScanner(text: string, ignoreTrivia: boolean = false): JSONScanner; | |
| /** | |
| * The scanner object, representing a JSON scanner at a position in the input string. | |
| */ | |
| export interface JSONScanner { | |
| /** | |
| * Sets the scan position to a new offset. A call to 'scan' is needed to get the first token. | |
| */ | |
| setPosition(pos: number): any; | |
| /** | |
| * Read the next token. Returns the token code. | |
| */ | |
| scan(): SyntaxKind; | |
| /** | |
| * Returns the zero-based current scan position, which is after the last read token. | |
| */ | |
| getPosition(): number; | |
| /** | |
| * Returns the last read token. | |
| */ | |
| getToken(): SyntaxKind; | |
| /** | |
| * Returns the last read token value. The value for strings is the decoded string content. For numbers it's of type number, for boolean it's true or false. | |
| */ | |
| getTokenValue(): string; | |
| /** | |
| * The zero-based start offset of the last read token. | |
| */ | |
| getTokenOffset(): number; | |
| /** | |
| * The length of the last read token. | |
| */ | |
| getTokenLength(): number; | |
| /** | |
| * The zero-based start line number of the last read token. | |
| */ | |
| getTokenStartLine(): number; | |
| /** | |
| * The zero-based start character (column) of the last read token. | |
| */ | |
| getTokenStartCharacter(): number; | |
| /** | |
| * An error code of the last scan. | |
| */ | |
| getTokenError(): ScanError; | |
| } | |
| ``` | |
| ### Parser: | |
| ```typescript | |
| export interface ParseOptions { | |
| disallowComments?: boolean; | |
| allowTrailingComma?: boolean; | |
| allowEmptyContent?: boolean; | |
| } | |
| /** | |
| * Parses the given text and returns the object the JSON content represents. On invalid input, the parser tries to be as fault tolerant as possible, but still return a result. | |
| * Therefore always check the errors list to find out if the input was valid. | |
| */ | |
| export declare function parse(text: string, errors?: {error: ParseErrorCode;}[], options?: ParseOptions): any; | |
| /** | |
| * Parses the given text and invokes the visitor functions for each object, array and literal reached. | |
| */ | |
| export declare function visit(text: string, visitor: JSONVisitor, options?: ParseOptions): any; | |
| /** | |
| * Visitor called by {@linkcode visit} when parsing JSON. | |
| * | |
| * The visitor functions have the following common parameters: | |
| * - `offset`: Global offset within the JSON document, starting at 0 | |
| * - `startLine`: Line number, starting at 0 | |
| * - `startCharacter`: Start character (column) within the current line, starting at 0 | |
| * | |
| * Additionally some functions have a `pathSupplier` parameter which can be used to obtain the | |
| * current `JSONPath` within the document. | |
| */ | |
| export interface JSONVisitor { | |
| /** | |
| * Invoked when an open brace is encountered and an object is started. The offset and length represent the location of the open brace. | |
| */ | |
| onObjectBegin?: (offset: number, length: number, startLine: number, startCharacter: number, pathSupplier: () => JSONPath) => void; | |
| /** | |
| * Invoked when a property is encountered. The offset and length represent the location of the property name. | |
| * The `JSONPath` created by the `pathSupplier` refers to the enclosing JSON object, it does not include the | |
| * property name yet. | |
| */ | |
| onObjectProperty?: (property: string, offset: number, length: number, startLine: number, startCharacter: number, pathSupplier: () => JSONPath) => void; | |
| /** | |
| * Invoked when a closing brace is encountered and an object is completed. The offset and length represent the location of the closing brace. | |
| */ | |
| onObjectEnd?: (offset: number, length: number, startLine: number, startCharacter: number) => void; | |
| /** | |
| * Invoked when an open bracket is encountered. The offset and length represent the location of the open bracket. | |
| */ | |
| onArrayBegin?: (offset: number, length: number, startLine: number, startCharacter: number, pathSupplier: () => JSONPath) => void; | |
| /** | |
| * Invoked when a closing bracket is encountered. The offset and length represent the location of the closing bracket. | |
| */ | |
| onArrayEnd?: (offset: number, length: number, startLine: number, startCharacter: number) => void; | |
| /** | |
| * Invoked when a literal value is encountered. The offset and length represent the location of the literal value. | |
| */ | |
| onLiteralValue?: (value: any, offset: number, length: number, startLine: number, startCharacter: number, pathSupplier: () => JSONPath) => void; | |
| /** | |
| * Invoked when a comma or colon separator is encountered. The offset and length represent the location of the separator. | |
| */ | |
| onSeparator?: (character: string, offset: number, length: number, startLine: number, startCharacter: number) => void; | |
| /** | |
| * When comments are allowed, invoked when a line or block comment is encountered. The offset and length represent the location of the comment. | |
| */ | |
| onComment?: (offset: number, length: number, startLine: number, startCharacter: number) => void; | |
| /** | |
| * Invoked on an error. | |
| */ | |
| onError?: (error: ParseErrorCode, offset: number, length: number, startLine: number, startCharacter: number) => void; | |
| } | |
| /** | |
| * Parses the given text and returns a tree representation the JSON content. On invalid input, the parser tries to be as fault tolerant as possible, but still return a result. | |
| */ | |
| export declare function parseTree(text: string, errors?: ParseError[], options?: ParseOptions): Node | undefined; | |
| export declare type NodeType = "object" | "array" | "property" | "string" | "number" | "boolean" | "null"; | |
| export interface Node { | |
| type: NodeType; | |
| value?: any; | |
| offset: number; | |
| length: number; | |
| colonOffset?: number; | |
| parent?: Node; | |
| children?: Node[]; | |
| } | |
| ``` | |
| ### Utilities: | |
| ```typescript | |
| /** | |
| * Takes JSON with JavaScript-style comments and remove | |
| * them. Optionally replaces every none-newline character | |
| * of comments with a replaceCharacter | |
| */ | |
| export declare function stripComments(text: string, replaceCh?: string): string; | |
| /** | |
| * For a given offset, evaluate the location in the JSON document. Each segment in the location path is either a property name or an array index. | |
| */ | |
| export declare function getLocation(text: string, position: number): Location; | |
| /** | |
| * A {@linkcode JSONPath} segment. Either a string representing an object property name | |
| * or a number (starting at 0) for array indices. | |
| */ | |
| export declare type Segment = string | number; | |
| export declare type JSONPath = Segment[]; | |
| export interface Location { | |
| /** | |
| * The previous property key or literal value (string, number, boolean or null) or undefined. | |
| */ | |
| previousNode?: Node; | |
| /** | |
| * The path describing the location in the JSON document. The path consists of a sequence strings | |
| * representing an object property or numbers for array indices. | |
| */ | |
| path: JSONPath; | |
| /** | |
| * Matches the locations path against a pattern consisting of strings (for properties) and numbers (for array indices). | |
| * '*' will match a single segment, of any property name or index. | |
| * '**' will match a sequence of segments or no segment, of any property name or index. | |
| */ | |
| matches: (patterns: JSONPath) => boolean; | |
| /** | |
| * If set, the location's offset is at a property key. | |
| */ | |
| isAtPropertyKey: boolean; | |
| } | |
| /** | |
| * Finds the node at the given path in a JSON DOM. | |
| */ | |
| export function findNodeAtLocation(root: Node, path: JSONPath): Node | undefined; | |
| /** | |
| * Finds the most inner node at the given offset. If includeRightBound is set, also finds nodes that end at the given offset. | |
| */ | |
| export function findNodeAtOffset(root: Node, offset: number, includeRightBound?: boolean) : Node | undefined; | |
| /** | |
| * Gets the JSON path of the given JSON DOM node | |
| */ | |
| export function getNodePath(node: Node): JSONPath; | |
| /** | |
| * Evaluates the JavaScript object of the given JSON DOM node | |
| */ | |
| export function getNodeValue(node: Node): any; | |
| /** | |
| * Computes the edit operations needed to format a JSON document. | |
| * | |
| * @param documentText The input text | |
| * @param range The range to format or `undefined` to format the full content | |
| * @param options The formatting options | |
| * @returns The edit operations describing the formatting changes to the original document following the format described in {@linkcode EditResult}. | |
| * To apply the edit operations to the input, use {@linkcode applyEdits}. | |
| */ | |
| export function format(documentText: string, range: Range, options: FormattingOptions): EditResult; | |
| /** | |
| * Computes the edit operations needed to modify a value in the JSON document. | |
| * | |
| * @param documentText The input text | |
| * @param path The path of the value to change. The path represents either to the document root, a property or an array item. | |
| * If the path points to an non-existing property or item, it will be created. | |
| * @param value The new value for the specified property or item. If the value is undefined, | |
| * the property or item will be removed. | |
| * @param options Options | |
| * @returns The edit operations describing the changes to the original document, following the format described in {@linkcode EditResult}. | |
| * To apply the edit operations to the input, use {@linkcode applyEdits}. | |
| */ | |
| export function modify(text: string, path: JSONPath, value: any, options: ModificationOptions): EditResult; | |
| /** | |
| * Applies edits to an input string. | |
| * @param text The input text | |
| * @param edits Edit operations following the format described in {@linkcode EditResult}. | |
| * @returns The text with the applied edits. | |
| * @throws An error if the edit operations are not well-formed as described in {@linkcode EditResult}. | |
| */ | |
| export function applyEdits(text: string, edits: EditResult): string; | |
| /** | |
| * An edit result describes a textual edit operation. It is the result of a {@linkcode format} and {@linkcode modify} operation. | |
| * It consist of one or more edits describing insertions, replacements or removals of text segments. | |
| * * The offsets of the edits refer to the original state of the document. | |
| * * No two edits change or remove the same range of text in the original document. | |
| * * Multiple edits can have the same offset if they are multiple inserts, or an insert followed by a remove or replace. | |
| * * The order in the array defines which edit is applied first. | |
| * To apply an edit result use {@linkcode applyEdits}. | |
| * In general multiple EditResults must not be concatenated because they might impact each other, producing incorrect or malformed JSON data. | |
| */ | |
| export type EditResult = Edit[]; | |
| /** | |
| * Represents a text modification | |
| */ | |
| export interface Edit { | |
| /** | |
| * The start offset of the modification. | |
| */ | |
| offset: number; | |
| /** | |
| * The length of the modification. Must not be negative. Empty length represents an *insert*. | |
| */ | |
| length: number; | |
| /** | |
| * The new content. Empty content represents a *remove*. | |
| */ | |
| content: string; | |
| } | |
| /** | |
| * A text range in the document | |
| */ | |
| export interface Range { | |
| /** | |
| * The start offset of the range. | |
| */ | |
| offset: number; | |
| /** | |
| * The length of the range. Must not be negative. | |
| */ | |
| length: number; | |
| } | |
| /** | |
| * Options used by {@linkcode format} when computing the formatting edit operations | |
| */ | |
| export interface FormattingOptions { | |
| /** | |
| * If indentation is based on spaces (`insertSpaces` = true), then what is the number of spaces that make an indent? | |
| */ | |
| tabSize: number; | |
| /** | |
| * Is indentation based on spaces? | |
| */ | |
| insertSpaces: boolean; | |
| /** | |
| * The default 'end of line' character | |
| */ | |
| eol: string; | |
| } | |
| /** | |
| * Options used by {@linkcode modify} when computing the modification edit operations | |
| */ | |
| export interface ModificationOptions { | |
| /** | |
| * Formatting options. If undefined, the newly inserted code will be inserted unformatted. | |
| */ | |
| formattingOptions?: FormattingOptions; | |
| /** | |
| * Default false. If `JSONPath` refers to an index of an array and `isArrayInsertion` is `true`, then | |
| * {@linkcode modify} will insert a new item at that location instead of overwriting its contents. | |
| */ | |
| isArrayInsertion?: boolean; | |
| /** | |
| * Optional function to define the insertion index given an existing list of properties. | |
| */ | |
| getInsertionIndex?: (properties: string[]) => number; | |
| } | |
| ``` | |
| License | |
| ------- | |
| (MIT License) | |
| Copyright 2018, Microsoft | |