Revision f5372506-4c77-48e4-a31a-fcd4fa9e2e2d - Code Golf Stack Exchange

# [JavaScript (Node.js)], 38 bytes

<!-- language-all: lang-javascript -->

 s=>s.replace(/(.)(.)(\s|$)/g,"2ドル1ドル3ドル")

[Try it online!][TIO-jbqap3g2]

RegExp approach, assuming words separated by only 1 space.

[JavaScript (Node.js)]: https://nodejs.org
[TIO-jbqap3g2]: https://tio.run/##bYyxCsIwFEV3v@JRMjSgLeooFQoqDp2ki@ASktc2GpOQl9rFf6/VUQpnu@eeu3gJkkH7uLJO4dgUIxV7ygJ6IySmeZrxLzd6M563y4Rt2JptEz7upLPkDGbGtWmTJnUnLD0Szhf/y9X1GGBAIx0@54S60wQTwoLw3uCcczLae91aqDBGpABlcL2yc2o8I7iDAtmVlTlabGHQXQQaprhCML/AZXqOHw "JavaScript (Node.js) – Try It Online"