JSON
Fixing JSON That Is Really a JavaScript Object Literal
Text copied from console.log, DevTools or a config file is often a JavaScript object, not JSON. What differs, what is lost, and how to convert it safely.
7 min read
Library
Everything you need to level up your coding skills.
YAML
Why a Number Turns Into Something Else in YAML Files
Leading zeros, hex, base 60 times and trailing zeros change what a number is. Real output for 0755, 12:30, 1.10 and 1e3, and how to protect values.
5 min read
JSON
Repairing Truncated JSON From a Cut Off Response or File
A response or file that stops mid-document fails with an end-of-input error. How to confirm truncation, salvage complete records and decide on repair.
8 min read
JSON
Fixing JSON With Unescaped Newlines in Strings Safely
A raw newline, tab or backslash inside a JSON string is invalid. See the errors Python and Node give, how strict=False helps and how to write strings safely.
8 min read
YAML
YAML Error Could Not Find Expected Colon and Its Causes
A line with a word and no colon makes the parser fail while scanning a simple key. See the message in three parsers, the usual causes and the fixes.
6 min read
XML
Pretty Printing XML to Spot Structural Mistakes Quickly
When a minified XML file will not parse, xmllint --format and lxml refuse to indent it. A 30-line tokenizer indents what it can and flags the first mismatch.
6 min read
JSON
Why JSON Parse Fails on a Byte Order Mark and How to Fix It
A UTF-8 byte order mark in front of JSON breaks strict parsers in Python and Node. What the three bytes are, who adds them and how to read or remove them.
7 min read
XML
Encoding Mismatch Errors in XML Documents From Mixed Sources
When an XML feed mixes encodings or was encoded twice: why detectors guess wrong on short text, the UTF-8 first rule and per-line fallback.
7 min read
YAML
YAML Error Did Not Find Expected Key and How to Fix It
Why a line indented between two levels raises did not find expected key, how PyYAML words it differently, and how to realign. Output from three parsers.
6 min read
JSON
Python JSONDecodeError Extra Data and Concatenated Objects
Extra data means a valid JSON value was followed by more text. Why concatenated objects and JSON Lines trigger it and three ways to read them in Python.
7 min read
XML
Fixing XML With Unescaped Ampersands From a Legacy Export
Repair a 29 MB XML export with 215,385 raw ampersands using a lookahead regex that leaves existing entities alone, with the cases that need judgment.
6 min read
JSON
Python JSONDecodeError Expecting Value Line 1 Column 1
Why json.loads or response.json() raises Expecting value at line 1 column 1 in Python, how to see what the text really is, and a checklist for each cause.
7 min read
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