Files
strom/src/functions/replace.ts
Jerry Kurian faac6134af Refactoring
2019-08-16 09:02:54 -04:00

34 lines
1.2 KiB
TypeScript

import { Transform } from "stream";
import { StringDecoder } from "string_decoder";
import { WithEncoding } from "./baseDefinitions";
/**
* Return a ReadWrite stream that replaces occurrences of the given string or regular expression in
* the streamed chunks with the specified replacement string
* @param searchValue Search string to use
* @param replaceValue Replacement string to use
* @param options
* @param options.encoding Encoding written chunks are assumed to use
*/
export function replace(
searchValue: string | RegExp,
replaceValue: string,
options: WithEncoding = { encoding: "utf8" },
): Transform {
const decoder = new StringDecoder(options.encoding);
return new Transform({
readableObjectMode: true,
transform(chunk: Buffer, encoding, callback) {
const asString = decoder.write(chunk);
// Take care not to break up multi-byte characters spanning multiple chunks
if (asString !== "" || chunk.length === 0) {
callback(
undefined,
asString.replace(searchValue, replaceValue),
);
} else {
callback();
}
},
});
}