Query String Plus Sign Becomes Space – + vs %2B Explained
Explain form-style query decoding where + represents a space while %2B represents a literal plus sign.
Read fixQuery String error index
Query String Troubleshooting
Resolve query-string parsing and building errors involving percent encoding, repeated parameters, empty values, fragments, arrays, and JSON inputs.
Diagnostic workflow
How to troubleshoot Query String problems
Query strings mix separators with percent-encoded data, so establish which characters are syntax and which belong to a value before decoding anything. When building a query string, start from the intended key-value model; when parsing one, preserve repeated and empty values until their meaning is known.
- Separate the leading question mark and any fragment first, then inspect ampersands and equals signs before applying percent decoding to keys or values.
- Preserve repeated parameters, empty strings, and flag-style keys during diagnosis instead of collapsing them into one value too early.
- When building from JSON, verify that nested objects, arrays, booleans, numbers, nulls, and Unicode values follow the exact encoding convention the receiver expects.
Browse focused fixes
Common Query String problems
24 troubleshooting pages
Repeated Query Parameters – Parse Duplicate Keys as Arrays
Show how repeated query keys are preserved as arrays in parse mode.
Read fixEmpty Query Parameter Value – Why name= Becomes an Empty String
Explain the difference between an empty query value and a missing parameter.
Read fixURL Fragment Ignored When Parsing Query String – # Explained
Explain that URL fragments are separate from the query component and are intentionally ignored by query parsing.
Read fixInvalid JSON When Building Query String – Fix JSON Parse Errors
Diagnose malformed JSON before query-string construction begins.
Read fixQuery String Builder Requires JSON Object – Fix Array or Scalar Input
Require a top-level JSON object so property names can become query parameter keys.
Read fixNested JSON Object Not Supported in Query String – Flatten or Serialize Values
Explain why nested JSON objects are rejected instead of being flattened with an undocumented convention.
Read fixUnsafe Integer in Query String JSON – Avoid JavaScript Precision Loss
Prevent silent precision loss when large integer-looking identifiers are represented as JSON numbers.
Read fixPercent-Encoded Ampersand in Query String – Use %26 Inside Values
Keep an ampersand inside a query value by encoding it as %26.
Read fixEquals Sign Inside Query Value – Decode %3D Correctly
Keep equals signs inside query values with %3D and inspect the decoded result.
Read fixPercent-Encoded Unicode in Query Strings – Decode UTF-8 Values
Inspect how UTF-8 percent escapes become Unicode text in parsed query parameters.
Read fixMalformed Percent Encoding in Query String – Why URLSearchParams Still Parses
Show how malformed percent-encoded UTF-8 can parse with replacement characters rather than raising an exception.
Read fixEmpty Query Parameter Name – Why =value Creates an Empty Key
Inspect empty-name query parameters and distinguish them from parameters with empty values.
Read fixQuery Parameter Without Equals – Why ?debug Becomes an Empty String
Explain URLSearchParams behavior for key-only query segments without an equals sign.
Read fixPercent-Encoded Query Parameter Name – Decode Spaces and Plus Signs in Keys
Decode percent escapes in query parameter names and inspect the resulting JSON keys.
Read fixNested URL in Query Parameter – Encode & and = Inside Redirect URLs
Show why embedded URLs must percent-encode their own query delimiters when used as an outer query value.
Read fixJSON Array to Repeated Query Parameters – Build Duplicate Keys
Show how Build Query maps arrays of primitive JSON values to repeated URLSearchParams keys.
Read fixJSON null in Query String – Why null Becomes an Empty Value
Explain the builder's intentional mapping from JSON null to an empty query parameter value.
Read fixEmpty JSON Array in Query String – Why No Parameter Is Emitted
Explain that an empty array has no primitive items to append and therefore emits no query pair for its key.
Read fixBoolean Query Parameters – Build true and false from JSON
Show the exact string representation used for JSON booleans in Build Query mode.
Read fixNumber Query Parameters – Build Integers and Decimals from JSON
Show how finite safe JSON numbers are stringified into query parameter values.
Read fixEmpty String Query Parameter – Build key= from JSON
Show that empty strings emit one explicit key= pair rather than disappearing from the query.
Read fixBuild Percent-Encoded Query String – Spaces, &, =, and Keys
Demonstrate form-url-encoded output for spaces and reserved characters in both keys and values.
Read fixUnicode to Query String – UTF-8 Percent Encoding for Text and Emoji
Show how URLSearchParams serializes Unicode strings as UTF-8 percent-encoded query components.
Read fixUnderstand the underlying concepts
Query String guides
1 related guides
Query String Encoding and Repeated Parameters Explained
Understand query string percent encoding, plus signs, repeated parameters, empty values, fragments, and how JSON arrays map to repeated query keys.
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