2016-03-23 19:00:53 +01:00

118 lines
2.5 KiB
JavaScript

import repeating from "repeating";
import jsTokens from "js-tokens";
import esutils from "esutils";
import chalk from "chalk";
/**
* Chalk styles for token types.
*/
let defs = {
string: chalk.red,
punctuator: chalk.bold,
curly: chalk.green,
parens: chalk.blue.bold,
square: chalk.yellow,
keyword: chalk.cyan,
number: chalk.magenta,
regex: chalk.magenta,
comment: chalk.grey,
invalid: chalk.inverse
};
/**
* RegExp to test for newlines in terminal.
*/
const NEWLINE = /\r\n|[\n\r\u2028\u2029]/;
/**
* Get the type of token, specifying punctuator type.
*/
function getTokenType(match) {
let token = jsTokens.matchToToken(match);
if (token.type === "name" && esutils.keyword.isReservedWordES6(token.value)) {
return "keyword";
}
if (token.type === "punctuator") {
switch (token.value) {
case "{":
case "}":
return "curly";
case "(":
case ")":
return "parens";
case "[":
case "]":
return "square";
}
}
return token.type;
}
/**
* Highlight `text`.
*/
function highlight(text: string) {
return text.replace(jsTokens, function (...args) {
let type = getTokenType(args);
let colorize = defs[type];
if (colorize) {
return args[0].split(NEWLINE).map((str) => colorize(str)).join("\n");
} else {
return args[0];
}
});
}
/**
* Create a code frame, adding line numbers, code highlighting, and pointing to a given position.
*/
export default function (
rawLines: string,
lineNumber: number,
colNumber: ?number,
opts: Object = {},
): string {
colNumber = Math.max(colNumber, 0);
let highlighted = opts.highlightCode && chalk.supportsColor;
if (highlighted) rawLines = highlight(rawLines);
let lines = rawLines.split(NEWLINE);
let start = Math.max(lineNumber - 3, 0);
let end = Math.min(lines.length, lineNumber + 3);
if (!lineNumber && !colNumber) {
start = 0;
end = lines.length;
}
let numberMaxWidth = String(end).length;
let frame = lines.slice(start, end).map((line, index) => {
let number = start + 1 + index;
let paddedNumber = ` ${number}`.slice(-numberMaxWidth);
let gutter = ` ${paddedNumber} | `;
if (number === lineNumber) {
let markerLine = colNumber
? `\n ${gutter.replace(/\d/g, " ")}${repeating(" ", colNumber - 1)}^`
: "";
return `>${gutter}${line}${markerLine}`;
} else {
return ` ${gutter}${line}`;
}
}).join("\n");
if (highlighted) {
return chalk.reset(frame);
} else {
return frame;
}
}